java使用UDP协议传输数据

来源：互联网发布：汪峰告旭日阳刚知乎编辑：程序博客网时间：2024/05/22 01:55

UDP协议（User Datagram Protocol,用户数据报协议）不同于TCP协议，它是不可能靠的，但是它比TCP协议具有更快的传输速度，UDP发送的数据单元称为数据报，当网络传输UDP传输UDP数据报是无法保证数据能够到达目的地，也无法保证按发送的顺序到达目的地，也就是说先发送了“hello”,再发送了“world”,但接收方可能会先收到“world”,再收到“hello”,也有可能收不到数据，为什么呢？因为它是不可能靠的，在传输途中可能丢失了。但UDP比TCP跟适合与传输实时音频。下面是一个简单的UPD传输数据报的例子

服务器端：

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;public class EchoServer {private DatagramSocket datagramSocket;private final int port = 8088;public static void main(String[] args) throws SocketException {new EchoServer().service();}public EchoServer() throws SocketException{datagramSocket = new DatagramSocket(port);System.out.println("服务器启动");}public String echo(String msg){return "echo:"+msg;}public void service(){while (true) {try {DatagramPacket packet = new DatagramPacket(new byte[512], 512);datagramSocket.receive(packet);String msg = new String(packet.getData(), 0, packet.getLength());System.out.println(packet.getAddress()+"/"+packet.getPort()+" msg:"+msg);packet.setData(echo(msg).getBytes());datagramSocket.send(packet);} catch (IOException e) {e.printStackTrace();}}}}

客户端：

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;public class EchoClient {private String remoteHost="localhost";private int remotePort=8088;private DatagramSocket datagramSocket;public EchoClient() throws SocketException{datagramSocket = new DatagramSocket();}public static void main(String[] args) throws SocketException {new EchoClient().talk();}public void talk(){try {BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));String msg = null;InetAddress address = InetAddress.getByName(remoteHost);while ((msg=reader.readLine())!=null) {//发送数据报byte [] buffer = msg.getBytes();DatagramPacket packet = new DatagramPacket(buffer,buffer.length, address, remotePort);datagramSocket.send(packet);//接收数据报DatagramPacket inputPacket = new DatagramPacket(new byte[512], 512);datagramSocket.receive(inputPacket);System.out.println(new String(inputPacket.getData(), 0 , inputPacket.getLength()));if("bye".equals(msg)){break;}}} catch (IOException e) {e.printStackTrace();}finally{datagramSocket.close();}}}

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