UDP实现服务器与客户端双向通信

package UDPconnection;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

public class UDPserver
{
public static void main(String args[]) throws Exception
{
DatagramSocket socket=new DatagramSocket();
String str="nice to meet you!";
//构造数据报包
DatagramPacket packet =new DatagramPacket(str.getBytes(),str.length(),InetAddress.getByName("localhost"),5000);
//发送
socket.send(packet);

byte []by=new byte[1024];
DatagramPacket repacket=new DatagramPacket(by,100);
socket.receive(repacket);
System.out.println(new String(by,0,repacket.getLength()));
socket.close();
}

package UDPconnection;

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

public class UDPclient
{
public static void main(String args[]) throws Exception
{
byte[] by=new byte[1024];
DatagramSocket socket=new DatagramSocket(7000);
DatagramPacket repacket=new DatagramPacket(by,by.length);
socket.receive(repacket);
System.out.println(new String(by,0,repacket.getLength()));
String str="I love You!";
DatagramPacket packet=new DatagramPacket(str.getBytes(),str.length(),repacket.getAddress(),repacket.getPort());

socket.send(packet);
socket.close();
}
}