TCP和UDP通信——多发多收
UDP通信
1.客户端可以反复发送数据
客户端实现步骤
(1)创建DatagramSocket对象(发送端对象)
(2)使用while死循环不断的接收用户的数据输入,如果用户输入”886”则退出程序
(3)使用DatagramSocket对象的send方法将数据包对象进行发送
(4)释放资源
public class UDPClient {public static void main(String[] args) throws IOException {Scanner sc = new Scanner(System.in);DatagramSocket client = new DatagramSocket(); //使用随机端口while (true) {//发送的信息由键盘录入System.out.println("请输入聊天内容:");String info = sc.next();byte[] bytes = info.getBytes();DatagramPacket dp = new DatagramPacket(bytes,bytes.length,InetAddress.getByName("127.0.0.1"),20000);client.send(dp);//循环发送如果输入"886"退出if (info.contains("886")) {System.out.println("正在下线..");client.close();break;}}}
}
2.接收端可以反复接收数据
1.接受端可以反复接收数据
接收端实现步骤
(1)创建DatagramSocket对象并指定端口(接收端对象)
(2)创建DatagramSocket对象接收数据(数据包对象)
(3)使用DatagramSocket对象的receive方法传入DatagramPacket对象
(4)暂且不释放资源,使用while死循环不断的进行第3步
public class UDPServer {public static void main(String[] args) throws IOException {System.out.println("=== 聊天室 ===");DatagramSocket server = new DatagramSocket(20000);//循环接收while (true) {byte[] bytes = new byte[1024];DatagramPacket dp = new DatagramPacket(bytes, bytes.length);server.receive(dp);//展示数据System.out.println(new String(bytes,0, dp.getLength()));//DatagramPacket对象获取客户端其他信息System.out.println(dp.getAddress().getHostAddress() + "/" + dp.getPort());//不要关闭服务器Socket对象,否则只能接一次System.out.println("-------------------");}}
}
TCP通信
1.客户端可以反复发送数据
实现步骤:
(1)客户端使用死循环,让用户不断输入消息
(2)服务端也使用死循环,控制服务端接收完消息,继续等到接收下一个消息
public class TCPClient {public static void main(String[] args) throws Exception {Scanner sc = new Scanner(System.in);Socket client = new Socket("127.0.0.1", 8888);OutputStream os = client.getOutputStream();DataOutputStream dos = new DataOutputStream(os);while (true) {System.out.println("请输入联调内容:");String info = sc.next();dos.writeUTF(info);dos.flush();//循环发送如果输入"886"退出if (info.contains("886")) {System.out.println("正在下线..");client.close();dos.close();break;}}}
}
2.接收端可以反复接收数据
public class TCPServer {public static void main(String[] args) throws Exception {System.out.println("=== 聊天室 ===");ServerSocket server = new ServerSocket(8888);Socket serverSocket = server.accept();InputStream is = serverSocket.getInputStream();DataInputStream dis = new DataInputStream(is);//循环接收while (true) {try {String info = dis.readUTF(); //有用户下线,会抛异常SocketExceptionSystem.out.println(info);} catch (Exception e) {//有人下线则释放资源System.out.println(serverSocket.getRemoteSocketAddress() + "离线了");System.out.println("-----------------------");server.close();dis.close();break;}}}
}
TCP通信-支持与多个客户端同时通信(多线程)
如何实现服务端同时接收多个客户端的消息的?
- 主线程定义了循环负责接收客户端Socket管道连接
- 没接收到一个Socket通信管道后分配给一个独立的线程负责处理它
客户端:
public class TCPClient {public static void main(String[] args) throws Exception {Scanner sc = new Scanner(System.in);Socket client = new Socket("127.0.0.1", 8888);OutputStream os = client.getOutputStream();DataOutputStream dos = new DataOutputStream(os);while (true) {System.out.println("请输入联调内容:");String info = sc.next();dos.writeUTF(info);dos.flush();//循环发送如果输入"886"退出if (info.contains("886")) {System.out.println("正在下线..");client.close();dos.close();break;}}}
}
任务类:封装本次连接的客户端要完成的逻辑
public class ServerThread implements Runnable {//serverSocket:本次连接的客户端的Socket对象private Socket serverSocket;public ServerThread(Socket serverSocket) {this.serverSocket = serverSocket;}@Overridepublic void run() {try {//接收数据InputStream is = serverSocket.getInputStream();DataInputStream dis = new DataInputStream(is);//循环接收while (true) {try {String info = dis.readUTF(); //有用户下线,会抛异常SocketExceptionSystem.out.println(info);} catch (Exception e) {//有人下线则释放资源System.out.println(serverSocket.getRemoteSocketAddress() + "离线了");System.out.println("-----------------------");serverSocket.close();dis.close();break;}}} catch (IOException e) {e.printStackTrace();}}
}
服务端:使用线程循环接收
package com.demo12_TCP多发多收_多线程实现;// TODO: 能够完成TCP通信下服务端可以同时接收多个客户端的消息import java.net.ServerSocket;
import java.net.Socket;public class TCPServer {public static void main(String[] args) throws Exception {System.out.println("=== 聊天室 ===");ServerSocket server = new ServerSocket(8888);while (true) {Socket serverSocket = server.accept();//每当服务器监听到一个连接请求,获取serverSocket对象,开启一个线程处理任务new Thread(new ServerThread(serverSocket)).start();}}
}