package com.bjpowernode.java_learning;

import java.io.*;

​

public class D101_1_DataOutputStream {

  public static void main(String[] args) throws IOException{

    //创建数据字节输出流

    String address = "C:\\\\Users\\\\lenovo1\\\\Workspaces\\\\MyEclipse CI\\\\Java_learning\\\\src\\\\com\\\\bjpowernode\\\\java_learning\\\\temp1.txt";

    DataOutputStream dos = new DataOutputStream(new FileOutputStream(address));

    //准备数据

    byte b = 10;

    short s = 11;

    int i = 12;

    long l = 13;

    float f = 3.2f;

    double d = 2.3;

    boolean flag = false;

    char c = 'a';

    //写入

    dos.writeByte(b);

    dos.writeShort(s);

    dos.writeInt(i);

    dos.writeLong(l);

    dos.writeFloat(f);

    dos.writeDouble(d);

    dos.writeBoolean(flag);

    dos.writeChar(c);

    //刷新

    dos.flush();

    //写进去的内容是二进制文件，我们使用文本打开都是一堆乱码

   

    //关闭

    dos.close();

   

    //创建输入流

    DataInputStream dis = new DataInputStream(new FileInputStream(address));

    //读

    //注意：要使用该流读取数据，必须提前知道该文件中的数据存储格式，顺序。

    byte b1 = dis.readByte();

    short s1 = dis.readShort();

    int i1 = dis.readInt();

    long l1 = dis.readLong();

    float f1 = dis.readFloat();

    double d1 = dis.readDouble();

    boolean flag1 = dis.readBoolean();

    char c1 = dis.readChar();

   

   

    System.out.println(b1);

    System.out.println(s1);

    System.out.println(i1);

    System.out.println(l1);

    System.out.println(f1);

    System.out.println(d1);

    System.out.println(flag1);

    System.out.println(c1);

    //用途：有点像加密文件，多见于电信行业，我们传输数据，然后告知对方我们的格式以及数据顺序，对方才可以解析出来

    //关闭

    dis.close();

   

   

  }

​

}

​

 

package com.bjpowernode.java_learning;

import java.io.*;

import java.util.Date;

import java.text.SimpleDateFormat;

​

public class D101_2_PrintStream {

  public static void main(String[] args) throws Exception {

    System.out.println("HelloWorld");

   

    PrintStream ps = System.out;

    ps.println("JAVA");

   

    String address = "C:\\\\Users\\\\lenovo1\\\\Workspaces\\\\MyEclipse CI\\\\Java_learning\\\\src\\\\com\\\\bjpowernode\\\\java_learning\\\\temp1.txt";

   

    //setOut方法可以改变输出方向，PrintStream(FileOutputStream f)可以接受字节输出流

   

    System.setOut(new PrintStream(new FileOutputStream(address)));

    //再次输出

    System.out.print("HAHA");

    //通常使用上述方法来记录日志

   

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");

    System.out.println(sdf.format(new Date()));

    m1();

    System.out.println(sdf.format(new Date()));

   

   

  }

  public static void m1() {

    System.out.println("m1 method execute");

  }

​

}