tcp编程

客户端编程：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;

public class ClientDemo {
  public static void main(String[] args)
    throws IOException {
    ClientDemo client = new ClientDemo();
    client.open();
  }
  private void open() throws IOException {
    //new Socket(host, port) 构造器会发起对host主机上
    // port端口 的连接, 如果连接成功就会创建Socket实例s
    // 如连接失败, 会抛出IOException实例.
    // 服务器必须先启动, 等待连接!
    Socket s = new Socket("localhost", 8000);
    //in 代表服务端到客户端的流
    InputStream in = s.getInputStream();
    //out 代表客户端到服务器的流
    OutputStream out = s.getOutputStream();
    new Reader(out, s).start();
    new Writer(in, s). start();
  }
  //负责读取控制台信息, 发送到服务器端.
  class Reader extends Thread{
    OutputStream out;
    Socket s;
    public Reader(OutputStream out, Socket s) {
      this.out = out;
      this.s = s;
    }
//  负责读取控制台信息, 发送到服务器端.
    public void run() {
      Scanner in = new Scanner(System.in);
      try{
        while(true){
          String str = in.nextLine();//粗面\n
          //System.out.println(str);//粗面
          out.write((str+"\n").getBytes());//一定发送 \n
          out.flush();
          if(str.equalsIgnoreCase("Bye")){
            this.s.close();
            break;
          }
        }
      }catch(Exception e){
        e.printStackTrace();
      }
    }
  }
  //负责将从服务器获取的信息显示到控制台, 后台线程, 自动结束
  class Writer extends Thread{
    InputStream in;
    Socket s;
    public Writer(InputStream in, Socket s) {
      this.in = in;
      this.s = s;
      setDaemon(true);
    }
//  负责将从服务器获取的信息显示到控制台, 后台线程, 自动结束
    public void run() {
      Scanner in = new Scanner(this.in);
      while(true){
        String str = in.nextLine();//没有.\n
        //System.out.println(str);//没有.
        System.out.println(str);
      }
    }
  }
}

服务器端编程：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class ServerDemo {
  public static void main(String[] args)
    throws IOException {
    ServerDemo server = new ServerDemo();
    server.start();
  }
  public void start() throws IOException {
    ServerSocket ss = new ServerSocket(8000);
    while(true){
    //ss.accept() 引起当前线程(main)IO Block, 等到客户端
    //的连接, 如果客户端连接成功就返回Socket实例 s
    //s代表客户端的连接, s中包含流属性: in和out,
    //in代表客户端发送来的信息, out代表向客户端输出的信息
    //开启客户端服务线程实例为客户服务, 主线程等待下个客户连接
      Socket s = ss.accept();
      new Service(s).start();
    }
  }
  class Service extends Thread{
    Socket s;
    public Service(Socket s) {
      this.s = s;
    }
    public void run() {
      try{
        InputStream in = s.getInputStream();
        OutputStream out = s.getOutputStream();
        out.write("欢迎光顾!你点些啥?\n".getBytes());
        out.flush();
        Scanner sc = new Scanner(in);
        while(true){
          String str = sc.nextLine();//粗面\n
          //System.out.println(str);//粗面
          if(str.equals("粗面")){
            out.write("没有.\n".getBytes());
            out.flush();
          } else if(str.equals("包子")){
            out.write("有, 给你!\n".getBytes());
            out.flush();
          } else if(str.equalsIgnoreCase("bye")){
            out.write("Bye!\n".getBytes());
            out.flush();
            this.s.close();
            break;
          }
        }
      }catch(IOException e){
        e.printStackTrace();
      }
    }
  }
}