[网络协议]UDP 发送接收

UDP

package com.qian;

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

import org.junit.Test;

/**
 * UDP 协议的网络协议
 * 
 * UDP 先启动接收端不会报错，但是 TCP 会报错
 */
public class UDPTest {

    // 发送端
    @Test
    public void sender() {

        DatagramSocket socket = null;
        try {
            socket = new DatagramSocket();

            String str = "我是 UDP 方式发送的导弹";
            byte[] data = str.getBytes();
            InetAddress inet = InetAddress.getLocalHost();
            DatagramPacket packet = new DatagramPacket(data, 0, data.length, inet, 9090);

            socket.send(packet);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (socket != null) {
                socket.close();
            }
        }
    }

    // 接收端
    @Test
    public void receiver() {

        DatagramSocket socket = null;
        try {
            socket = new DatagramSocket(9090);

            byte[] buffer = new byte[100];
            DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);

            socket.receive(packet);

            System.out.println(new String(packet.getData(), 0, packet.getLength()));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            socket.close();
        }
    }
}