Java IO API记录
文件路径：
public static final String FILEPATH= File.separator+"Users"+ File.separator+"xuminzhe"+ File.separator+"Documents"+File.separator+"io";
1.创建文件
public static void main(String[] args) {
File file=new File(Constant.FILEPATH+File.separator+"io.text");
try {
boolean newFile = file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
2.查找指定目录下文件
public static void main(String[] args) {
File file=new File(Constant.FILEPATH);
File[] str = file.listFiles();
for (int i = 0; i < str.length; i++) {
System.out.println(str[i]);
}
}
3.文件流-写入
String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); OutputStream outputStream=new FileOutputStream(file,true); byte[] bytes = "你好".getBytes(); for (int i = 0; i < bytes.length; i++) { outputStream.write(bytes[i]); } outputStream.close();
4.文件流-读取
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); InputStream inputStream=new FileInputStream(file); /** * 单字节读取 */ { byte[] bytes = new byte[1024]; int read1; int count =0; while((read1 = inputStream.read())!=-1){ bytes[count++]=(byte) read1; } System.out.println(new String(bytes)); } /** * 多字节读取 */ { byte[] bytes=new byte[(int) file.length()]; int read; while((read=inputStream.read(bytes))!=-1){ System.out.println(new String (bytes)); } } }
5.字符流-写入
String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); Writer writer=new FileWriter(file,true); String str="\r\nhello"; writer.write(str); writer.close();
6.字符流-读取
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); Reader read=new FileReader(file); char[] ch=new char[100]; int temp=0; int count=0; while((temp=read.read())!=(-1)){ ch[count++]=(char)temp; } read.close(); System.out.println("内容为"+new String(ch,0,count)); }
7.转换流-写入 将输出的字符流转化为字节流
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); Writer writer=new java.io.OutputStreamWriter(new FileOutputStream(file,true)); writer.write("kobe"); writer.close(); }
8.转换流-读取 将输入的字节流转换为字符流
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); Reader read = new InputStreamReader(new FileInputStream(file)); char[] b=new char[100]; int len=read.read(b); System.out.println(new String(b,0,len)); read.close(); }
9.对象流
static String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; static File file=new File(filename); public static void main(String[] args) throws Exception { serializable(file); deserializable(file); } /** * 反序列化 * @param file * @throws IOException * @throws ClassNotFoundException */ private static void deserializable(File file) throws IOException, ClassNotFoundException { ObjectInputStream stream=new ObjectInputStream(new FileInputStream(file)); Person o = (Person) stream.readObject(); System.out.println(o.toString()); } /** * 序列化对象 * @param file * @throws IOException */ private static void serializable(File file) throws IOException { ObjectOutputStream outputStream=new ObjectOutputStream(new FileOutputStream(file,true)); outputStream.writeObject(new Person("xmz",13)); outputStream.close(); }
10.缓冲字符流-读取
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); BufferedReader bufferedReader=new BufferedReader(new FileReader(file)); String line; while((line=bufferedReader.readLine())!=null){//读取一个文本行 System.out.println(line); } bufferedReader.close(); }
11.缓冲字符流-写入
public static void main(String[] args) throws IOException { String filename=Constant.FILEPATH+ File.separator+"HELLO.text"; File file=new File(filename); FileWriter fileWriter=new FileWriter(file); /** * 为了提高写入的效率，使用了字符流的缓冲区。 * 创建了一个字符写入流的缓冲区对象，并和指定要被缓冲的流对象相关联。 */ BufferedWriter bufferedWriter=new BufferedWriter(fileWriter); bufferedWriter.write("jordan乔丹"); bufferedWriter.newLine();//换行 bufferedWriter.write("kobe蜗壳"); bufferedWriter.write("wade韦德"); bufferedWriter.flush(); bufferedWriter.close(); }
12 管道流-可用于线程通信
static class Send implements Runnable{ private PipedOutputStream out=null; public Send() { out=new PipedOutputStream(); } public PipedOutputStream getOut(){ return this.out; } public void run(){ String message="hello，xmz"; try{ out.write(message.getBytes()); }catch (Exception e) { e.printStackTrace(); }try{ out.close(); }catch (Exception e) { e.printStackTrace(); } } } /** * 接受消息类 * */ static class Recive implements Runnable{ private PipedInputStream input=null; public Recive(){ this.input=new PipedInputStream(); } public PipedInputStream getInput(){ return this.input; } public void run(){ byte[] b=new byte[1000]; int len=0; try{ len=this.input.read(b); }catch (Exception e) { e.printStackTrace(); }try{ input.close(); }catch (Exception e) { e.printStackTrace(); } System.out.println("接受的内容为 "+(new String(b,0,len))); } } public static void main(String[] args) throws IOException { Send send=new Send(); Recive recive=new Recive(); try{ //管道连接 send.getOut().connect(recive.getInput()); }catch (Exception e) { e.printStackTrace(); } new Thread(send).start(); new Thread(recive).start(); }
