网络编程+IO+多线程

随机产生结果（刚刚学完网络编程顺手做了一个小程序）

import java.net.ServerSocket; import java.net.Socket; import java.util.Scanner; import java.io.PrintStream; class MyThread implements Runnable{ private Socket client; public MyThread(Socket client){ this.client=client; } public void run(){ try{ Scanner in = new Scanner(this.client.getInputStream()); in.useDelimiter("\n"); PrintStream out = new PrintStream(this.client.getOutputStream()); boolean flag = true; while(flag){ if(in.hasNext()){ String data = in.next().trim(); if(“exit”.equalsIgnoreCase(data)){ flag = false; out.println(“程序结束，再见”); }else{ out.println(“ECHO:”+data); } } } this.client.close(); }catch(Exception e){ e.printStackTrace(); } } } public class EchoServer{ public static void main(String[] args) throws Exception { ServerSocket server = new ServerSocket(9999); System.out.println(“服务端开启…”); boolean flag =true; while(flag){ Socket client = server.accept(); new Thread(new MyThread(client)).start(); } server.close(); } } import java.net.ServerSocket; import java.net.Socket; import java.io.PrintStream; import java.util.Random; public class EchoClient{ public static void main(String[] args) throws Exception{ Socket client = new Socket(“localhost”,9999); Scanner in = new Scanner (client.getInputStream()); in.useDelimiter("\n"); PrintStream out = new PrintStream(client.getOutputStream()); Random r=new Random(); int num=r.nextInt(5); switch(num){ case 1: System.out.println(“麻辣烫”); break; case 2: System.out.println(“披萨”); break; case 3: System.out.println(“奶茶”); break; case 4: System.out.println(“火锅”); break; case 5: System.out.println(“冰激凌”); break; default: System.out.println(“error”); break; } client.close(); } }