import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
import java.text.*;

public class MouseMove{
        public static void main(String[] args){
  MouseFrame frame = new MouseFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.show();
  }  
}

/*
 * JFrame
 * @author yung
 */
class MouseFrame extends JFrame{
  public MouseFrame(){
  setTitle("MouseTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        MousePanel panel = new MousePanel();
        Container contentPane = getContentPane();
        contentPane.add(panel);
     }

     public static final int DEFAULT_WIDTH = 300;
     public static final int DEFAULT_HEIGHT = 200;  
}

/*
 * JPanel
 * @author yung
 */
class MousePanel extends JPanel{
    public MousePanel(){
    label = new HLabel(message,url);
    label.setFont(new Font("Simsun",20,20));
    add(label,BorderLayout.CENTER);
    }
    
     private HLabel label;
     private String message="Hello Bupt";
     private String url="http://www.bupt.edu.cn";
}

/*
 * HLabel
 * @author yung
 */
class HLabel extends JLabel{
  private String url;    //链接网址
  private Rectangle bounds; //字符区域
  boolean flag = true;  //判断鼠标在字符区域内的标志
  
  /*
   * constructor
   */
  public HLabel(String text,String uurl){
    super(text);
    url=uurl;
    setHorizontalAlignment(SwingConstants.CENTER);
    bounds=new Rectangle();
  }
  
  //当点击链接时打开网页  
  public void openIt() {
    try {
      Runtime.getRuntime().exec("mozilla "+url);
      }catch (Exception e) {
      JOptionPane.showMessageDialog(this,e.getMessage(),"Error",JOptionPane.ERROR_MESSAGE);
    }
  }
  
  
  //当鼠标移到链接上字体变为蓝色，然后重绘，鼠标变为手形
  public void blue(){
    flag = false;      
    repaint();
    setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
  }
  
  //鼠标在其他地方，鼠标为默认。
  public void black(){
    flag = true;
    repaint();
    setCursor(Cursor.getDefaultCursor());  
  }
    
  
  
  //paint
  public void paint(Graphics g) {
      super.paintBorder(g);//括号里是g，不知怎么显示不出来
    
      Graphics2D g2=(Graphics2D)g;
      
      //获取label上字符属性    
      Font f=getFont();
      AttributedString ats=new AttributedString(this.getText());
      ats.addAttribute(TextAttribute.FONT, f);
      ats.addAttribute(TextAttribute.UNDERLINE,TextAttribute.UNDERLINE_ON);
      AttributedCharacterIterator iter=ats.getIterator();
      FontRenderContext frc=g2.getFontRenderContext(); 
    
      TextLayout tl=new TextLayout(iter, frc);
      
      //重绘时根据flag来判断是变为蓝色还是黑色
      if(flag==true){
        g2.setColor(Color.black);
      }else{
        g2.setColor(Color.BLUE);
      }
      
      //获取字符区域  
      Rectangle rect=tl.getBounds().getBounds();
      Rectangle total=this.getBounds();
      bounds.x=(total.width-rect.width)/2;
      bounds.y=(total.height-rect.height)/2;
      bounds.width=rect.width;
      bounds.height=rect.height;
      tl.draw(g2,bounds.x,bounds.y+rect.height);
      
      //添加监听器
      addMouseListener(new MouseHandler());
      addMouseMotionListener(new MouseMotionHandler());    
  }
  
  
  //查找鼠标所在点是否在字符的区域内  
  public Rectangle2D find(Point2D p){
      if (bounds.contains(p)) return bounds; //括号里是p，也没显示出来
      return null;
  }
    
  //鼠标点击的事件处理
  private class MouseHandler extends MouseAdapter {
    public void mouseClicked(MouseEvent event){
      if(SwingUtilities.isLeftMouseButton(event)) {
        if(event.getClickCount()==1) {
          if(find(event.getPoint())!=null) {
            openIt();         
          }
        }
      }
    }
  }
     
     //鼠标移动的事件处理
  private class MouseMotionHandler implements MouseMotionListener{
    public void mouseMoved(MouseEvent event){
      if (find(event.getPoint()) == null){
        black();   //调用默认鼠标方法
        
      }
      else{
        blue();   //调用显示链接为蓝色方法
        
      }
    }
       
    public void mouseDragged(MouseEvent event){
         
    }
  }
}