一个简单的用JAVA实现的屏幕抓图(源代码)

import java.io.*;
import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.io.*;

/**
 * @Author Qiu_BaiChao 一个简单的屏幕抓图 主要使用的是java.util.Robot类来捕获屏幕,可以实现对屏幕一个矩形区域的捕获,
 * 通过这个类,我们也可以实现一个远程桌面控制的程序
*
 */
public class ScreenCapture {
//test main
    public static void main(String[] args) throws Exception {
        String userdir = System.getProperty("user.dir");
        File tempFile = new File("d:", "temp.png");
        ScreenCapture capture = ScreenCapture.getInstance();
        capture.captureImage();
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());
        JLabel imagebox = new JLabel();
        panel.add(BorderLayout.CENTER, imagebox);
        imagebox.setIcon(capture.getPickedIcon());
        capture.saveToFile(tempFile);
        capture.captureImage();
        imagebox.setIcon(capture.getPickedIcon());
        frame.setContentPane(panel);
        frame.setSize(400, 300);
        frame.show();
        System.out.println("Over");
    }

    private ScreenCapture() {

        try {
            robot = new Robot();
        } catch (AWTException e) {
            System.err.println("Internal Error: " + e);
            e.printStackTrace();
        }
        JPanel cp = (JPanel) dialog.getContentPane();
        cp.setLayout(new BorderLayout());
        labFullScreenImage.addMouseListener(new MouseAdapter() {

            public void mouseReleased(MouseEvent evn) {
                isFirstPoint = true;
                pickedImage = fullScreenImage.getSubimage(recX, recY, recW, recH);
                dialog.setVisible(false);
            }
        });

        labFullScreenImage.addMouseMotionListener(new MouseMotionAdapter() {

            public void mouseDragged(MouseEvent evn) {
                if (isFirstPoint) {
                    x1 = evn.getX();
                    y1 = evn.getY();
                    isFirstPoint = false;
                } else {
                    x2 = evn.getX();
                    y2 = evn.getY();
                    int maxX = Math.max(x1, x2);
                    int maxY = Math.max(y1, y2);
                    int minX = Math.min(x1, x2);
                    int minY = Math.min(y1, y2);
                    recX = minX;
                    recY = minY;
                    recW = maxX - minX;
                    recH = maxY - minY;
                    labFullScreenImage.drawRectangle(recX, recY, recW, recH);
                }
            }

            public void mouseMoved(MouseEvent e) {
                labFullScreenImage.drawCross(e.getX(), e.getY());
            }
        });

        cp.add(BorderLayout.CENTER, labFullScreenImage);
        dialog.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
        dialog.setAlwaysOnTop(true);
        dialog.setMaximumSize(
                Toolkit.getDefaultToolkit().getScreenSize());
        dialog.setUndecorated(true);
        dialog.setSize(dialog.getMaximumSize());
        dialog.setModal(true);
    }
//Singleton Pattern
    public static ScreenCapture getInstance() {
        return defaultCapturer;
    }

    /**
     * 捕捉全屏慕
     */
    public Icon captureFullScreen() {
        fullScreenImage = robot.createScreenCapture(new Rectangle(
                Toolkit.getDefaultToolkit().getScreenSize()));
        ImageIcon icon = new ImageIcon(fullScreenImage);
        return icon;
    }

    /**
     * 捕捉屏幕的一个矫形区域
     */
    public void captureImage() {
        fullScreenImage = robot.createScreenCapture(new Rectangle(
                Toolkit.getDefaultToolkit().getScreenSize()));
        ImageIcon icon = new ImageIcon(fullScreenImage);
        labFullScreenImage.setIcon(icon);
        dialog.setVisible(true);
    }

    /**
     * 得到捕捉后的BufferedImage
     */
    public BufferedImage getPickedImage() {
        return pickedImage;
    }

    /**
     * 得到捕捉后的Icon
     */
    public ImageIcon getPickedIcon() {
        return new ImageIcon(getPickedImage());
    }

    /**
     * 储存为一个文件,为PNG格式
     *
     * @deprecated replaced by saveAsPNG(File file)
*
     */
    @Deprecated
    public void saveToFile(File file) throws IOException {
        ImageIO.write(getPickedImage(), defaultImageFormater, file);
    }

    /**
     * 储存为一个文件,为PNG格式
     */
    public void saveAsPNG(File file) throws IOException {
        ImageIO.write(getPickedImage(), "png", file);
    }

    /**
     * 储存为一个JPEG格式图像文件
     */
    public void saveAsJPEG(File file) throws IOException {
        ImageIO.write(getPickedImage(), "JPEG", file);
    }

    /**
     * 写入一个OutputStream
     */
    public void write(OutputStream out) throws IOException {
        ImageIO.write(getPickedImage(), defaultImageFormater, out);
    }
//singleton design pattern
    private static ScreenCapture defaultCapturer = new ScreenCapture();
    private int x1, y1, x2, y2;
    private int recX, recY, recH, recW; //截取的图像
    private boolean isFirstPoint = true;
    private BackgroundImage labFullScreenImage = new BackgroundImage();
    private Robot robot;
    private BufferedImage fullScreenImage;
    private BufferedImage pickedImage;
    private String defaultImageFormater = "png";
    private JDialog dialog = new JDialog();
}

/**
 * 显示图片的Label
 */
class BackgroundImage extends JLabel {

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawRect(x, y, w, h);
        String area = Integer.toString(w) + " * " + Integer.toString(h);
        g.drawString(area, x + (int) w / 2 - 15, y + (int) h / 2);
        g.drawLine(lineX, 0, lineX, getHeight());
        g.drawLine(0, lineY, getWidth(), lineY);
    }

    public void drawRectangle(int x, int y, int width, int height) {
        this.x = x;
        this.y = y;
        h = height;
        w = width;
        repaint();
    }

    public void drawCross(int x, int y) {
        lineX = x;
        lineY = y;
        repaint();
    }
    int lineX, lineY;
    int x, y, h, w;
}