java中利用udp实现发送数据

1.udp的特点

1. 数据以包的形式发送数据
2. udp是面向无连接的
3. udp会丢失数据，是一种不安全的连接
4. udp的传输速度较快

2.发送端

package cn.uu710.SocketTest;

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

public class Send1 {

	public static void main(String[] args) {
		try {
			DatagramSocket datagramSocket = new DatagramSocket();
			String data = "这是张佑发送的消息！";
			DatagramPacket datagramPacket = new DatagramPacket(data.getBytes(),data.getBytes().length,InetAddress.getLocalHost(),8088);
			//发送
			System.out.println("正在准备发送……");
			datagramSocket.send(datagramPacket);
			System.out.println("已发送……");
			datagramSocket.close();
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

}

3.接收端

package cn.uu710.SocketTest;

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

import com.sun.org.apache.bcel.internal.generic.NEW;

public class receive1 {

	public static void main(String[] args) {
		try {
			DatagramSocket datagramSocket = new DatagramSocket(8088);
			byte[] b = new byte[1024];
			DatagramPacket datagramPacket = new DatagramPacket(b,b.length);
			System.out.println("正在准备接收……");
			//未接收之前为阻塞状态
			datagramSocket.receive(datagramPacket);
			System.out.println("接收内容："+new String(b,0,b.length));
			System.out.println("已经接收……");
			datagramSocket.close();
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}

4. 运行程序

先启动接收端，再运行发送端
启动接收端后，程序并未停止，因为还未接收到消息

再启动发送端，此时接收端成功接收到消息，之后程序停止