java网络编程(4)——udp实现聊天

　　UDP可以实现在线聊天功能，我这里就是简单模拟一下：
　　发送端：

package com.seven.udp;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class CharByUpdSend implements Runnable {

    private DatagramSocket ds;

    public CharByUpdSend(DatagramSocket ds) {
        this.ds = ds;
    }

    @Override
    public void run() {
        try {
            // 输入
            BufferedReader bufr = new BufferedReader(new InputStreamReader(
                    System.in));

            String line = null;
            while ((line = bufr.readLine()) != null) {

                DatagramPacket dp = new DatagramPacket(line.getBytes(),
                        line.length(), InetAddress.getByName("127.0.0.1"),
                        10001);

                ds.send(dp);

            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

　　接收端：

package com.seven.udp;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class CharByUpdReceive implements Runnable{

    private DatagramSocket ds ;
    public CharByUpdReceive(DatagramSocket ds) {
        this.ds = ds;
    }

    @Override
    public void run() {
        try{
            while(true){
                byte[] buf = new byte[1024];
                DatagramPacket dp = new DatagramPacket(buf, buf.length);
                ds.receive(dp);
                String data = new String(dp.getData(),0,dp.getLength());
                System.out.println(dp.getAddress()+"-->"+data);
            }

        }catch(Exception e){
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
}

　　主程序：

package com.seven.udp;

import java.net.DatagramSocket;

public class CharDemo {

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

        DatagramSocket send = new DatagramSocket();
        DatagramSocket receive = new DatagramSocket(10001);

        new Thread(new CharByUpdSend(send)).start();
        new Thread(new CharByUpdReceive(receive)).start();

    }
}

先启动接受方，然后启动发送方，这样就可以实现一个小小聊天效果，虽然这是在本机上，只要地址和端口对得上，这样就可以实现在线聊天！