Java ImageIO非常慢 [英] Java ImageIO is insanely slow

问题描述

我正在制作一个程序，将客户端屏幕发送到服务器并显示它，但速度非常慢。一帧需要2-3秒，上传/下载速度不是问题。有什么我做错了/我可以改变什么以加快速度吗？

I'm making a program that sends the clients screen to the server and displays it but it's being extremely slow. It's taking 2-3 seconds for one frame and the upload/download speed is not a problem. Is there anything I'm doing wrong/anything I can change to speed this up?

服务器：

import java.awt.BorderLayout;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.zip.GZIPInputStream;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class Server {

    public static void main(String[] args) {
        try {
            JPanel panel = new JPanel();
            panel.setLayout(new BorderLayout());

            JLabel label = new JLabel();
            label.setSize(800, 600);
            label.setVisible(true);

            JScrollPane scroll = new JScrollPane();
            scroll.getViewport().add(label);
            panel.add(scroll, BorderLayout.CENTER);

            JFrame frame = new JFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.getContentPane().add(panel);
            frame.setSize(800, 600);
            frame.setVisible(true);

            ServerSocket serverSocket = new ServerSocket(25565);
            Socket socket = serverSocket.accept();
            GZIPInputStream in = new GZIPInputStream(socket.getInputStream());
            BufferedImage image = null;
            while(socket.isConnected()) {
                image = ImageIO.read(in);
                if(image != null) {
                    label.setIcon(new ImageIcon(image));
                    label.repaint();

                }
            }
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户：

import java.awt.AWTException;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.io.IOException;
import java.net.Socket;
import java.util.zip.GZIPOutputStream;

import javax.imageio.ImageIO;

public class Client {

    public static void main(String[] args) {
        try {
            Robot robot = new Robot();
            Toolkit toolkit = Toolkit.getDefaultToolkit();
            Rectangle screen = new Rectangle((int) toolkit.getScreenSize().getWidth(), (int) toolkit.getScreenSize().getHeight());
            Socket socket = new Socket("127.0.0.1", 25565);
            GZIPOutputStream out = new GZIPOutputStream(socket.getOutputStream());

            while(socket.isConnected()) {
                ImageIO.write(robot.createScreenCapture(screen), "png", out);
            }
            out.close();
        } catch (AWTException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

推荐答案

如果您将图像作为 png 发送，则GZIPStream可能是个坏主意。由于png已经具有良好的压缩性，因此不会获得显着的压缩增益。根据图像的类型，您还可以考虑 jpeg 以实现更好的压缩。

If you are sending the image as png the GZIPStream is probable a bad idea. You won't achieve a signicant compression gain as png already has good compression. Depending on the kind of image you can also consider jpeg to achieve better compression.

但可能最重要的是使用BufferedOuputStream包装输出流：

But probably the most important is wrapping the output stream with a BufferedOuputStream:

BufferedOutputStream out = new BufferedOutputStream(socket.getOutputStream());

您可以在输入流中执行相同操作。

You can do the same in the input stream.

这篇关于Java ImageIO非常慢的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！