1

我以前遇到过这个问题，但我不记得我是如何解决的。我正在研究 RAT，到目前为止它只是将客户端屏幕发送到服务器。我曾经将图像保存到磁盘，但现在我试图让它只显示在 JFrame 上。它显示第一个屏幕截图，但仅显示第一个屏幕截图，它不会绘制新的屏幕截图。

服务器：

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;

import javax.imageio.ImageIO;
import javax.swing.JFrame;

@SuppressWarnings("serial")
public class Server extends JFrame {

private BufferedImage image;
private BufferedImage oldImage;

public Server() {
    setTitle("RAT");
    setResizable(false);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public static void main(String[] args) throws IOException {
    try {
        Server server = new Server();

        ServerSocket serverSocket = new ServerSocket(25565);
        Socket clientSocket = serverSocket.accept();
        System.out.println("Connection accepted!");

        ObjectInputStream in = new ObjectInputStream(clientSocket.getInputStream());
        boolean firstConnection = true;

        int width = 0;
        int height = 0;

        while (true) {
            if(firstConnection) {
                width = in.readShort();
                height = in.readShort();
                server.setSize(width, height);
                server.setVisible(true);
                firstConnection = false;
            }
            server.oldImage = ImageIO.read(in);
            if(server.oldImage != null) {
                server.image = server.oldImage;
            }
            server.repaint();

        }
    } catch (IOException e) {
        System.err.println("Accept failed.");
        System.exit(1);
    }
}

public void paint(Graphics g) {
    g.drawImage(image, 0, 0, this);
}
}

客户：

import java.awt.AWTException;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.Socket;

import javax.imageio.ImageIO;

public class Client {

public static void main(String[] args) {
    try {
        Socket socket = new Socket("127.0.0.1", 25565);
        ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
        Robot robot = new Robot();
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Rectangle rectangle = new Rectangle(toolkit.getScreenSize());
        out.writeShort(toolkit.getScreenSize().width);
        out.writeShort(toolkit.getScreenSize().height);

        while(true) {
            ImageIO.write(robot.createScreenCapture(rectangle), "jpg", out);
            Thread.sleep(200);
        }
    } catch (AWTException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}
}
4

2 回答 2

4

据我理解的问题，这是你阻塞事件调度线程的问题，通过编写类似Thread.sleep()or的东西while(true)，从 Swing 的角度来看，这确实不适合。

你可以做些什么来解决这个问题：

  • 在SwingWorker中引入循环结构。
  • 直接使用像 Socket 这样的代码片段clientSocket = serverSocket.accept();会阻止 EDT，因此这些事情必须在单独的Thread或内部完成SwingWorker。
  • 递归调用repaint()得到合并来自肮脏富客户的报价如下，以证明上述主题的合理性 
It is important to note that repaint requests get “coalesced,” or combined. 
So, for example, if you request a repaint and there is already one on the 
queue that has not yet been serviced, then the second request is ignored 
because your request for a repaint will already be fulfilled by the earlier 
request. This behavior is particularly helpful in situations where many
repaint requests are being generated, perhaps by very different situations 
and components, and Swing should avoid processing redundant requests and 
wasting effort.

这是一个示例程序，可提供进一步帮助：

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;

public class PointsExample
{   
    private CustomPanel contentPane;
    private Timer timer;
    private int x = 1;
    private int y = 1;

    /*
     * This is just JFrame, that we be 
     * using as the Base for our Application.
     * Though here we are calling our
     * JPanel (CustomPanel), whose
     * paintComponent(...) method, we had
     * override.
     */
    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("Locate Mouse Position");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        contentPane = new CustomPanel();
        frame.setContentPane(contentPane);  
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);

        for (int i = 0; i < 500; i++)
        {
            contentPane.set(x, y);
            x++;
            y++;
            if (x == 450)
                break;
        }
    }

    public static void main(String\u005B\u005D args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new PointsExample().createAndDisplayGUI();
            }
        });
    }
}

class CustomPanel extends JComponent
{
    private int x;
    private int y;

    public void set(int a, int b)
    {
        x = a;
        y = b;
        paintImmediately(0, 0, getWidth(), getHeight());

    }   

    @Override
    public Dimension getPreferredSize()
    {
        return (new Dimension(500, 500));
    }

    @Override
    public void paintComponent(Graphics g)
    { 
        super.paintComponent(g);
        g.clearRect(0, 0, getWidth(), getHeight());
        g.fillOval(x, y, 4, 4);                        
    }
}
于 2012-06-18T03:50:11.900 回答
0

看起来对 paint() 的初始调用发生在image == null. 这可能不是唯一的问题，但必须解决。

于 2012-06-18T02:22:16.677 回答