發短信：不用連接，需要知道對方地址

文章目錄

• UDP發送消息
• 實現互相聊天
• UDP多線程實現聊天

UDP發送消息

UDP傳輸
我們要用UDP傳輸數據時，怎么用Socket建立連接呢？
DatagramSocket與DatagramPacket
建立發送端，接收端。
建立數據包。
調用Socket的發送接收方法。
關閉Socket。
發送端與接收端是兩個獨立的運行程序。

package com.ayv.try03;import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; import java.nio.charset.StandardCharsets;public class UdpClientDemo01 {public static void main(String[] args) throws Exception {//建立一個socketDatagramSocket socket = new DatagramSocket();//建一個包String msg="hello 服務器";InetAddress localhost = InetAddress.getByName("localhost");int port=9090;//數據，數據的長度起始，要發給誰DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length);//發送包socket.send(packet);//關閉流socket.close();} }

接收端

package com.ayv.try03;import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException;public class UdpServeDemo01 {public static void main(String[] args) throws Exception {//開放端口DatagramSocket socket = new DatagramSocket(9090);//接收數據包byte[] buffer = new byte[1024];DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);socket.receive(packet);//阻塞接收//輸出包裹System.out.println(packet.getAddress().getHostAddress());System.out.println(new String(packet.getData(),0, packet.getLength()));//關閉鏈接socket.close();} }

care：端口

實現互相聊天

package com.ayv.chat;import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress; import java.net.SocketException;public class UdpSenderDamo01 {public static void main(String[] args) throws Exception {DatagramSocket socket = new DatagramSocket(8888);//準備數據：控制臺讀取System.inBufferedReader reader = new BufferedReader(new InputStreamReader(System.in));//循環發送消息while(true){String data= reader.readLine();byte[] datas = data.getBytes();DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 6666));socket.send(packet);if(data.equals("bye")){break;}}socket.close();} } package com.ayv.chat;import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException;public class UdpReceive {public static void main(String[] args) throws Exception {DatagramSocket socket = new DatagramSocket(6666);while(true){//準備接收包裹byte[] container = new byte[1024];DatagramPacket packet = new DatagramPacket(container, 0, container.length);socket.receive(packet);//阻塞式接收包裹//輸出byte[] data = packet.getData();String receiveDate = new String(data, 0, data.length);System.out.println(receiveDate);//斷開鏈接if(receiveDate.equals("bye")){break;}}socket.close();} }

UDP多線程實現聊天

通過多線程實現聊天程序，我們就要開啟兩個線程，一個接收數據，一個發送數據，這樣我就可以實現在一個窗口發送和接收數據了

package com.ayv.chat;import sun.jvm.hotspot.debugger.Address;public class TalkSyudent {public static void main(String[] args) {//開啟兩個線程new Thread(new TalkSend(7777,"localhost",9999)).start();new Thread(new TalkReceive(8888,"老師")).start();} } package com.ayv.chat;public class TalkTeacher {public static void main(String[] args) {new Thread(new TalkSend(5555,"localhost",8888)).start();new Thread(new TalkReceive(9999,"學生")).start();} } package com.ayv.chat;import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket;public class TalkReceive implements Runnable{DatagramSocket socket=null;private int port;private String msgForm;public TalkReceive(int port, String msgForm) {this.port=port;this.msgForm=msgForm;try {socket = new DatagramSocket(port);} catch (Exception e) {e.printStackTrace();}}@Overridepublic void run() {while(true){try {byte[] container = new byte[1024];DatagramPacket packet = new DatagramPacket(container, 0, container.length);socket.receive(packet);byte[] data = packet.getData();String receiveData = new String(data, 0, data.length);System.out.println(msgForm+":"+receiveData);if(receiveData.equals("bye")){break;}} catch (IOException e) {e.printStackTrace();}}socket.close();} } package com.ayv.chat;import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress; import java.net.SocketException;public class TalkSend implements Runnable{DatagramSocket socket=null;BufferedReader reader=null;private int fromPort;private String toIP;private int toPort;public TalkSend(int fromPort,String toIP,int toPort) {this.fromPort=fromPort;this.toIP=toIP;this.toPort=toPort;try {socket=new DatagramSocket(fromPort);reader=new BufferedReader(new InputStreamReader(System.in));} catch (Exception e) {e.printStackTrace();}}@Overridepublic void run() {while(true){try {String data=reader.readLine();byte[] datas = data.getBytes();DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress(this.toIP, this.toPort));socket.send(packet);if(data.equals("bye")){break;}} catch (Exception e) {e.printStackTrace();}}socket.close();} }

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