UDP通信实践
UDP(user datagram protocol用户数据报协议)通信实践<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
主要用到的类
DatagramSocket:用于接收,发送DatagramPacket
DatagramPacket:信息载体,指定ip和端口可以用DatagramSocket发送,不指定则用户接收数据包
InetAddress:网络地址(ip),InetAddress.getByName(null);获取本机地址(参数为域名或ip)
1.
package com.sk.udp;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
public class Sender {
private DatagramSocket ds;
private DatagramPacket dp;
public Sender() throws SocketException{
//创建socket实例,端口3333
ds=new DatagramSocket(3333);
}
public void send(String msg,String ip,int port) throws IOException{
byte[] buf=msg.getBytes();
//创建数据包,指定数据包存储地,长度,要发送的ip,端口
dp=new DatagramPacket(buf,buf.length,InetAddress.getByName(ip),port);
//发送数据包
ds.send(dp);
//创建空数据包准备接收数据
dp=new DatagramPacket(buf,buf.length);
//接收数据
ds.receive(dp);
System.out.println(new String(buf)+":"+dp.getAddress());
//关闭socket
ds.close();
}
public static void main(String[] args) {
try {
new Sender().send("msg", "192.168.1.103", 8888);
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
2
package com.sk.udp;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
public class Receiver implements Runnable{
private DatagramSocket ds;
private DatagramPacket dp;
public Receiver() throws SocketException{
ds=new DatagramSocket(8888);
}
public String receive() throws IOException{
byte[] buf=new byte[1024];
dp=new DatagramPacket(buf,1024);
ds.receive(dp);
ds.close();
return new String(buf)+":"+dp.getAddress();
}
public void run() {
// TODO Auto-generated method stub
byte[] buf=new byte[1024];
System.out.println("ready");
try {
dp=new DatagramPacket(buf,1024);
ds.receive(dp);
InetAddress addr=dp.getAddress();
int port=dp.getPort();
dp=new DatagramPacket(buf,1024,addr,port);
ds.send(dp);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
try {
new Thread(new Receiver()).start();
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}