Hadoop之HDFS客户端操作
1. HDFS 客户端环境准备
1.1 windows 平台搭建 hadoop 2.8.5
2. 创建Maven工程
# pom.xml
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.8.5</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.8.5</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.8.5</version>
</dependency>
</dependencies>
<build>
<plugins>
<!--java 的编译版本 1.8-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
2.1 配置src/main/resources/log4j.properties
## 输出到控制台
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
## 输出到文件
#log4j.appender.logfile=org.apache.log4j.FileAppender
#log4j.appender.logfile.File=target/spring.log
#log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
#log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
2.2 创建HDFSClient类
public class HDFSClient {
public static void main(String[] args) {
Configuration conf = new Configuration();
// NameNode地址
conf.set("fs.defaultFS", "hdfs://服务器IP地址:9000");
try {
// 1. 获取hdfs客户端对象
FileSystem fs = FileSystem.get(conf);
// 2. 在hdfs上创建路径
fs.mkdirs(new Path("/0526/noodles"));
// 3. 关闭资源
fs.close();
// 4. 程序结束
System.out.println("操作结束==========");
} catch (IOException e) {
e.printStackTrace();
}
}
}
2.2.1 异常处理
- “Permission denied”
2.3 HDFSClient类（升级版）
import java.net.URI;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class HDFSClient {
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
// 1. 获取hdfs客户端对象
FileSystem fs = FileSystem.get(new URI("hdfs://服务器IP地址:9000"), conf, "root");
// 2. 在hdfs上创建路径
fs.mkdirs(new Path("/0526/test002"));
// 3. 关闭资源
fs.close();
// 4. 程序结束
System.out.println("操作结束==========");
}
}
参考资料：
