Java将服务器绘制的线条同步到客户端的代码

以下是一个简单的 Java 代码示例，演示了如何将服务器绘制的线条同步到客户端：

服务端代码：

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class Server {
    private List<ClientHandler> clients = new ArrayList<>();

    public void start(int port) throws IOException {
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("Server started on port " + port);

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

            ClientHandler clientHandler = new ClientHandler(clientSocket, this);
            clients.add(clientHandler);
            clientHandler.start();
        }
    }

    public void broadcast(String message) {
        for (ClientHandler client : clients) {
            client.sendMessage(message);
        }
    }

    public static void main(String[] args) throws IOException {
        Server server = new Server();
        server.start(8080);
    }
}

class ClientHandler extends Thread {
    private Socket clientSocket;
    private Server server;
    private String name;
    private PrintWriter out;

    public ClientHandler(Socket clientSocket, Server server) {
        this.clientSocket = clientSocket;
        this.server = server;
    }

    public void run() {
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            out = new PrintWriter(clientSocket.getOutputStream(), true);

            out.println("Enter your name:");
            name = in.readLine();

            String welcomeMessage = "Welcome, " + name + "!";
            server.broadcast(welcomeMessage);

            while (true) {
                String input = in.readLine();
                if (input == null) {
                    return;
                }
                server.broadcast(name + ": " + input);
            }
        } catch (IOException e) {
            System.out.println("Error handling client: " + e);
        } finally {
            try {
                clientSocket.close();
            } catch (IOException e) {
            }
        }
    }

    public void sendMessage(String message) {
        out.println(message);
    }
}

客户端代码：

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Client {
    private String serverAddress;
    private int serverPort;
    private String name;
    private PrintWriter out;
    private JFrame frame;
    private DrawPanel drawPanel;
    private List<Point> points = new ArrayList<>();

    public Client(String serverAddress, int serverPort) {
        this.serverAddress = serverAddress;
        this.serverPort = serverPort;
    }

    public void start() throws Exception {
        Socket socket = new Socket(serverAddress, serverPort);
        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        out = new PrintWriter(socket.getOutputStream(), true);

        while (true) {
            String line = in.readLine();
            if (line.startsWith("Enter your name")) {
                out.println(name);
                break;
            }
        }

        frame = new JFrame("Drawing");
        drawPanel = new DrawPanel();

        frame.getContentPane().add(drawPanel);
        frame.setSize(400, 400);
        frame.setVisible(true);

        frame.addMouseMotionListener(new MouseMotionAdapter() {
            public void mouseDragged(MouseEvent e) {
                Point point = e.getPoint();
                points.add(point);
                drawPanel.repaint();
            }
        });

        while (true) {
            String line = in.readLine();
            if (line == null) {
                return;
            }
            drawPanel.addMessage(line);
        }
    }

    public static void main(String[] args) throws Exception {
        Client client = new Client("127.0.0.1", 8080);
        client.name = JOptionPane.showInputDialog("Enter your name:");
        client.start();
    }

    class DrawPanel extends JPanel {
        private List<String> messages = new ArrayList<>();

        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D) g;
            g2.setStroke(new BasicStroke(2));

            for (int i = 0; i < points.size() - 1; i++) {
                Point p1 = points.get(i);
                Point p2 = points.get(i + 1);
                g2.drawLine(p1.x, p1.y, p2.x, p2.y);
            }
        }

        public void addMessage(String message) {
            messages.add(message);
            repaint();
        }

        public void paintMessages(Graphics g) {
            g.setColor(Color.BLUE);
            int y = 15;
            for (String message : messages) {
                g.drawString(message, 5, y);
                y += 15;
            }
        }
    }
}

这个示例演示了一个简单的多人在线协同绘制程序。客户端可以绘制线条，并将其同步到服务器和其他客户端。服务器维护一个客户端列表，可以将收到的消息广播给所有连接的客户端。客户端使用 Java AWT 绘制线条和消息。