java如何实现网络聊天室

在Java中实现网络聊天室，你可以使用套接字编程（Socket Programming）

1. 创建服务器端：

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

public class ChatServer {
    public static void main(String[] args) throws IOException {
        int port = 12345;
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("Server is listening on port " + port);

        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("New client connected");

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

            String message;
            while ((message = in.readLine()) != null) {
                System.out.println("Received: " + message);
                broadcastMessage(out, message);
            }

            socket.close();
            System.out.println("Client disconnected");
        }
    }

    private static void broadcastMessage(PrintWriter out, String message) {
        for (Socket socket : clients) {
            if (socket != null && !socket.isClosed()) {
                out.println(message);
            }
        }
    }

    private static List clients = new ArrayList<>();
}

2. 创建客户端：

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

public class ChatClient {
    public static void main(String[] args) throws IOException {
        String serverAddress = "localhost";
        int port = 12345;

        Socket socket = new Socket(serverAddress, port);
        System.out.println("Connected to server");

        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String userInput;

        while (true) {
            System.out.println("Enter your message: ");
            userInput = stdIn.readLine();
            if (userInput != null && !userInput.isEmpty()) {
                out.println(userInput);
                broadcastMessage(in, userInput + " (" + socket.getInetAddress() + ")");
            }
        }
    }

    private static void broadcastMessage(BufferedReader in, String message) throws IOException {
        for (Socket socket : clients) {
            if (socket != null && !socket.isClosed()) {
                PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
                out.println(message);
            }
        }
    }
}

这个示例中，服务器端监听12345端口，当客户端连接时，服务器将接收到的消息广播给所有连接的客户端。客户端可以发送消息给服务器，然后服务器将消息广播给其他客户端。

请注意，这个示例仅用于演示目的，实际应用中可能需要考虑更多的功能和优化，例如多个频道、用户身份验证等。