自各儿写的屏幕截图软件,大家一起学习

import java.awt.*; 

 import java.awt.datatransfer.*; 
 import java.awt.event.*; 
 import java.awt.image.BufferedImage; 
 import java.io.*; 

 import javax.swing.*; 
 import javax.swing.filechooser.FileFilter; 

 import com.sun.image.codec.jpeg.*; 

 @SuppressWarnings("serial") 
 class ImagePanel extends JPanel 
 { 
 	private BufferedImage image; 

 	public ImagePanel(BufferedImage image) 
 	{ 
 		this.image = image; 
 		prefSize(); 
 	} 

 	public void setImage(BufferedImage image) 
 	{ 
 		this.image = image; 
 		prefSize(); 
 		repaint(); 
 	} 

 	/** 
 	 * 设置面板大小 
 	 */ 
 	private void prefSize() 
 	{ 
 		this.setSize(image.getWidth(), image.getHeight()); 
 	} 

 	@Override 
 	public void paintComponent(Graphics g) 
 	{ 
 		super.paintComponent(g); 
 		g.drawImage(image, 0, 0, null); 
 	} 
 } 

 /** 
  * 文件类型 
  */ 
 class ImageFilter extends FileFilter 
 { 

 	public boolean accept(File f) 
 	{ 
 		if (f.isDirectory()) 
 		{ 
 			return true; 
 		} 

 		String extension = getExtension(f); 
 		if (extension != null) 
 		{ 
 			if (extension.equals("jpeg") || extension.equals("jpg") 
 					|| extension.equals("bmp")) 
 			{ 
 				return true; 
 			} else 
 			{ 
 				return false; 
 			} 
 		} 

 		return false; 
 	} 

 	public String getExtension(File f) 
 	{ 
 		String ext = null; 
 		String s = f.getName(); 
 		int i = s.lastIndexOf('.'); 

 		if (i > 0 && i  < s.length() - 1) 
 		{ 
 			ext = s.substring(i + 1).toLowerCase(); 
 		} 
 		return ext; 
 	} 

 	public String getDescription() 
 	{ 
 		return "图片类型"; 
 	} 
 } 

 @SuppressWarnings("serial") 
 public class CutScreen extends JFrame 
 { 
 	private int x, y, w, h; 
 	private BufferedImage bufImage; 
 	private ImagePanel imagePanel; 
 	private Graphics g; 
 	private static Dimension screenDims; 
 	private GraphicsDevice gd = GraphicsEnvironment 
 			.getLocalGraphicsEnvironment().getDefaultScreenDevice(); 
 	private JPopupMenu popup = new JPopupMenu(); 
 	private JMenuItem[] popupm = 
 	{ new JMenuItem("Copy"), new JMenuItem("Save"), new JMenuItem("Reset"), 
 			new JMenuItem("Exit") }; 
 	private JFileChooser fileChooser = new JFileChooser(); 

 	public CutScreen() 
 	{ 

 		this.setLayout(new BorderLayout()); 
 		this.add(buildControls()); 

 		// 设置标题 
 		this.setTitle("截图程序"); 
 		// 去掉窗口的装饰 
 		this.setUndecorated(true); 
 		// 采用指定的窗口装饰风格 
 		this.getRootPane().setWindowDecorationStyle(JRootPane.NONE); 
 		// 设置全屏 
 		gd.setFullScreenWindow(this); 
 		// 窗体始终靠前 
 		this.setAlwaysOnTop(true); 
 		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

 	} 

 	private JComponent buildControls() 
 	{ 
 		// 获取屏幕图像 
 		bufImage = getScreenImage(); 
 		imagePanel = new ImagePanel(bufImage); 

 		// 注册事件监听 
 		imagePanel.addMouseListener(new MouseAdapter() 
 		{ 

 			// 当鼠标按下时 
 			public void mousePressed(MouseEvent e) 
 			{ 
 				// 获取按下时的鼠标坐标 
 				x = e.getX(); 
 				y = e.getY(); 
 			} 

 			public void mouseReleased(MouseEvent e) 
 			{