Socket类

以下是一个简单的 Java Socket 示例代码，展示了如何创建一个简单的客户端和服务器端，实现基本的通信：

服务器端代码：

import java.io.*;
import java.net.*;

public class Server {

    public static void main(String[] args) {
        final int portNumber = 8080;

        try (ServerSocket serverSocket = new ServerSocket(portNumber)) {
            System.out.println("Server started. Listening on port " + portNumber);

            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("Client connected: " + clientSocket);

                // 为每个客户端连接创建一个新线程来处理
                new ServerThread(clientSocket).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class ServerThread extends Thread {
    private Socket socket;

    public ServerThread(Socket socket) {
        this.socket = socket;
    }

    public void run() {
        try (
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()))
        ) {
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println("Received from client: " + inputLine);
                out.println("Server received: " + inputLine);
            }
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户端代码：

import java.io.*;
import java.net.*;

public class Client {

    public static void main(String[] args) {
        final String host = "localhost";
        final int portNumber = 8080;

        try (
            Socket socket = new Socket(host, portNumber);
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in))
        ) {
            String userInput;
            while ((userInput = stdIn.readLine()) != null) {
                out.println(userInput);
                System.out.println("Server response: " + in.readLine());
            }
        } catch (UnknownHostException e) {
            System.err.println("Unknown host: " + host);
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: " + host);
            System.exit(1);
        }
    }
}

这个示例实现了一个简单的基于 Socket 的客户端-服务器端通信。服务器端在本地监听指定端口（8080），客户端连接到该端口并发送消息，服务器端接收到消息后发送回应。