java文件操作

1、文件写入和
如何使用 write() 方法向文件写入内容？

复制代码
package Practice;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  FileWrite("C:\文档\个人学习资料\IOTest\rainbow.txt");
  }
  /
  • @Description: 文件写入
  • @Param: [str]
  • @return: void
  • @Author: BigData
  • @Date: 2020/11/5
    */
    private static void FileWrite(String str)
    {
    BufferedWriter out = null;
    try {
    out = new BufferedWriter(new FileWriter(str));
    out.write("文件写入");
    out.close();
    System.out.println("文件创建成功！");
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=62849:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
文件创建成功！

Process finished with exit code 0
2、读取文件
如何使用 readLine() 方法来读取文件 test.log 内容？

复制代码
package Practice;

import java.io.*;

/**

• @program: FlinkUdf

• @description: IO文件流

• @author: BigData

• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String str="C:\文档\个人学习资料\IOTest\rainbow.txt";
  readValue(str);
  }
  /

  • @Description: 读取文件内容
  • @Param: [str]
  • @return: void
  • @Author: BigData
  • @Date: 2020/11/5
    */
    private static void readValue(String str)
    {
    try {
    BufferedReader in=new BufferedReader(new FileReader(str));
    String s;
    while ((s=in.readLine())!=null)
    {
    System.out.println(s);
    }
    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }

  }
  }
  复制代码
  结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=62944:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
文件写入

Process finished with exit code 0
3、删除文件
如何使用 delete() 方法将文件删除？

复制代码
package Practice;

import java.io.*;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String str="C:\文档\个人学习资料\IOTest\rainbow.txt";
  delFile(str);
  }
  /
  • @Description: 删除文件（/+a+tab键）
  • @Param: [str]
  • @return: void
  • @Author: BigData
  • @Date: 2020/11/5
    */
    private static void delFile(String str)
    {
    try {
    File file=new File(str);
    if(file.delete()==true)
    {
    System.out.println(file.getName()+"文件已经被删除!");
    }
    else
    {
    System.out.println("文集删除失败！");
    }
    }
    catch (Exception ex)
    {
    ex.printStackTrace();
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=63028:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
rainbow.txt文件已经被删除!

Process finished with exit code 0

4、将文件内容复制到另一个文件
复制代码
package Practice;

import java.io.*;

/**

• @program: FlinkUdf

• @description: IO文件流

• @author: BigData

• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String str="C:\文档\个人学习资料\IOTest\rainbow.txt";
  String string="C:\文档\个人学习资料\IOTest\rainbow1.txt";
  copyFile(str,string);
  }
  /

  • @Description: 复制文件内容到另外文件中
  • @Param: [string]
  • @return: void
  • @Author: BigData
  • @Date: 2020/11/5
    */
    private static void copyFile(String string,String string1)
    {
    try {
    BufferedWriter out=new BufferedWriter(new FileWriter(string));
    out.write("复制文件");
    out.close();
    InputStream in=new FileInputStream(new File(string));
    OutputStream out1=new FileOutputStream(new File(string1));
    byte[] buf=new byte[1024];
    int len;
    while ((len=in.read(buf))>0)
    {
    out1.write(buf,0,len);
    }
    in.close();
    out1.close();
    BufferedReader in1=new BufferedReader(new FileReader(string1));
    String s;
    while ((s=in1.readLine())!=null)
    {
    System.out.println(s);
    }
    in1.close();
    } catch (IOException e) {
    e.printStackTrace();
    }

  }
  }
  复制代码
  结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=63140:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
复制文件

Process finished with exit code 0
5、向文件中追加数据

复制代码
package Practice;

import com.sun.org.glassfish.gmbal.Description;

import java.io.*;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String str="C:\文档\个人学习资料\IOTest\rainbow2.txt";
  String string="追加的内容";
  appendContent(str,string);
  }
  /
  • @Description:追加内容
  • @Param:
  • @return:
  • @Author: BigData
  • @Date: 2020/11/6
    */
    private static void appendContent(String str,String s)
    {
    try {
    BufferedWriter out=new BufferedWriter(new FileWriter(str));
    out.write("原内容--->>>>");
    out.close();
    //1.注意
    out=new BufferedWriter(new FileWriter(str,true));
    out.write(s);
    out.close();
    BufferedReader in=new BufferedReader(new FileReader(str));
    String string;
    while ((string=in.readLine())!=null)
    {
    System.out.println(string);
    }
    }
    catch (Exception ex)
    {
    System.out.println("错误内容："+ex);
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=50466:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
原内容--->>>>追加的内容

Process finished with exit code 0

6、创建临时文件
如何使用 File 类的 createTempFile(String prefix, String suffix); 方法在默认临时目录来创建临时文件，参数 prefix 为前缀，suffix 为后缀？

复制代码
package Practice;

import com.sun.org.glassfish.gmbal.Description;

import java.io.*;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String path="C:\文档\个人学习资料\IOTest\";
  String file="test";
  String fmt=".txt";
  creatTmpFile(path,file,fmt);
  }
  /
  • @Description: 根据文件路径，文件名和文件格式来创建临时文件
  • @Param:
  • @return:
  • @Author: BigData
  • @Date: 2020/11/9
    */
    private static void creatTmpFile(String path,String file,String fmt)
    {
    File f=null;
    try {
    //创建临时文件
    f=File.createTempFile(file,fmt,new File(path));
    // 输出绝对路径
    System.out.println("临时文件绝对路径："+f.getAbsolutePath());
    // 终止后删除临时文件
    f.deleteOnExit();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=54225:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
临时文件绝对路径：C:\文档\个人学习资料\IOTest\test8748305055128945538.txt

Process finished with exit code 0
7、修改文件最后的修改日期
如何使用 File 类的 fileToChange.lastModified() 和 fileToChange setLastModified() 方法来修改文件最后的修改日期？

复制代码
package Practice;

import com.sun.org.glassfish.gmbal.Description;

import java.io.*;
import java.util.Date;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String path="C:\文档\个人学习资料\IOTest\rainbow.txt";
  updateFileTime(path);
  }
  /
  • @Description: 修改文件的日期
  • @Param:
  • @return:
  • @Author: BigData
  • @Date: 2020/11/9
    */
    private static void updateFileTime(String path)
    {
    File file=new File(path);
    try {
    file.createNewFile();
    Date date=new Date(file.lastModified());
    System.out.println(date.toString());
    System.out.println(file.setLastModified(System.currentTimeMillis()));
    date=new Date(file.lastModified());
    System.out.println(date.toString());
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=54324:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
Thu Nov 05 17:42:25 CST 2020
true
Mon Nov 09 09:40:12 CST 2020

Process finished with exit code 0

8、获取文件大小
如何使用 File 类的 file.exists() 和 file.length() 方法来获取文件大小，以字节计算（1KB=1024字节 ）？

复制代码
package Practice;

import com.sun.org.glassfish.gmbal.Description;

import java.io.*;
import java.util.Date;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String path="C:\文档\个人学习资料\IOTest\rainbow.txt";
  System.out.println(path+"的文件大小是："+getFileSize(path));
  }
  /
  • @Description: 获取文件的大小
  • @Param: [filename]
  • @return: long
  • @Author: BigData
  • @Date: 2020/11/9
    */
    public static long getFileSize(String filename) {
    File file = new File(filename);
    if (!file.exists() || !file.isFile()) {
    System.out.println("文件不存在");
    return -1;
    }
    return file.length();
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=54409:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
C:\文档\个人学习资料\IOTest\rainbow.txt的文件大小是：12

Process finished with exit code 0

9、文件重命名

复制代码
package Practice;

import com.sun.org.glassfish.gmbal.Description;

import java.io.File;
import java.io.IOException;

/**

• @program: FlinkUdf
• @description: IO文件流
• @author: BigData
• @create: 2020-11-05 17:18
  /
  public class Test {
  public static void main(String[] args) {
  String oldName="C:\文档\个人学习资料\IOTest\rainbow.txt";
  String newName="C:\文档\个人学习资料\IOTest\rainbowTest.txt";
  renameFileName(oldName,newName);
  }
  /
  • @Description: 重命名文件名
  • @Param:
  • @return:
  • @Author: BigData
  • @Date: 2020/11/9
    */
    public static void renameFileName(String oldName,String newName) {
    File oldFile=new File(oldName);
    File newFile=new File(newName);
    if(newFile.exists())
    {
    try {
    throw new java.io.IOException("文件已经存在");
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    if(oldFile.renameTo(newFile))
    {
    System.out.println(oldName+"重命名为:"+newName);
    }
    else
    {
    System.out.println("错误命名");
    }
    }
    }
    复制代码
    结果：

"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=54757:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test
C:\文档\个人学习资料\IOTest\rainbow.txt重命名为:C:\文档\个人学习资料\IOTest\rainbowTest.txt

Process finished with exit code 0

10、设置文件只读
使用 File 类的 file.setReadOnly() 和 file.canWrite() 方法来设置文件只读

复制代码
import java.io.File;

public class Main {
public static void main(String[] args) {
File file = new File("C:/java.txt");
System.out.println(file.setReadOnly());
System.out.println(file.canWrite());
}
}
复制代码
结果：

true
false

11、检测文件是否存在
使用 File 类的 file.exists() 方法来检测文件是否存在

复制代码
import java.io.File;

public class Main {
public static void main(String[] args) {
File file = new File("C:/java.txt");
System.out.println(file.exists());
}
}
复制代码
12、在指定目录中创建文件
复制代码
import java.io.File;

public class Main {
public static void main(String[] args) throws Exception {
File file = null;
File dir = new File("C:/");
file = File.createTempFile
("JavaTemp", ".javatemp", dir);
System.out.println(file.getPath());
}
复制代码
结果：

C:\JavaTemp37056.javatemp
13、获取文件修改时间
复制代码
import java.io.File;
import java.util.Date;

public class Main {
public static void main(String[] args) {
File file = new File("Main.java");
Long lastModified = file.lastModified();
Date date = new Date(lastModified);
System.out.println(date);
}
}
复制代码
结果：

Thu Apr 09 09:40:19 CST 2015

14、创建文件
复制代码
import java.io.File;
import java.io.IOException;

public class Main {
public static void main(String[] args) {
try{
File file = new File("C:/myfile.txt");
if(file.createNewFile())
System.out.println("文件创建成功！");
else
System.out.println("出错了，该文件已经存在。");
}
catch(IOException ioe) {
ioe.printStackTrace();
}
}
}
复制代码
结果：

文件创建成功！

15、文件路径比较
使用 File 类的 filename.compareTo (another filename) 方法来比较两个文件路径是否在同一个目录下：

复制代码
import java.io.File;

public class Main {
public static void main(String[] args) {
File file1 = new File("C:/File/demo1.txt");
File file2 = new File("C:/java/demo1.txt");
if(file1.compareTo(file2) == 0) {
System.out.println("文件路径一致！");
} else {
System.out.println("文件路径不一致！");
}
}
}