数据流

DataInputStream 数据输入流
DataOutputStream 数据输出流
可以格式化读入读出

import java.io.*;
public class Test {
    public static void main(String[] args) {
        write();
        read();
    }
    private static void read(){
        File f = new File("D:\\test");
        try(
                FileInputStream fis = new FileInputStream(f);
                DataInputStream dis = new DataInputStream(fis)
        ){
            //读bool,int和string(UTF编码)
            boolean b = dis.readBoolean();
            int i = dis.readInt();
            String str = dis.readUTF();
            System.out.println("读取到布尔值:"+b);
            System.out.println("读取到整数:"+i);
            System.out.println("读取到字符串:"+str);
        }catch(IOException e){
            e.printStackTrace();
        }
    }
    private static void write(){
        File f = new File("D:\\test");
        try(
                FileOutputStream fos = new FileOutputStream(f);
                DataOutputStream dos = new DataOutputStream(fos);
            ){
            dos.writeBoolean(true);
            dos.writeInt(300);
            dos.writeUTF("123 this is gareen");
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}