JAVA 正则表达式匹配器

import javax.swing.*;     
import javax.swing.text.DefaultHighlighter;     
import javax.swing.text.BadLocationException;     
import java.awt.BorderLayout;     
import java.awt.Font;     
import java.awt.HeadlessException;     
import java.awt.Color;     
import java.awt.event.ActionEvent;     
import java.awt.event.ActionListener;     
import java.util.regex.Pattern;     
import java.util.regex.Matcher;     
      
/**   
 * 测试 Java 正则表达式   
 */     
public class RegTester {     
      
    public static void main(String[] args) {     
        try {     
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());     
        } catch (Exception e) {     
            e.printStackTrace();     
        }     
      
        new RegTesterFrame().setVisible(true);     
    }     
}     
      
class RegTesterFrame extends JFrame {     
      
    private JTextField textbox = new JTextField();  // 包含测试文本的文本域     
          
    private JTextArea textarea = new JTextArea();   // 包含正则表达式的文本框     
      
    private RegTesterFrame thisFrame = this;     
          
    private DefaultHighlighter.DefaultHighlightPainter highlightPainter =     
            new DefaultHighlighter.DefaultHighlightPainter(Color.green);     
      
    // 构造方法     
    RegTesterFrame() throws HeadlessException {     
        super("测试 Java 正则表达式");     
        setSize(500, 300);     
        setLocation(300, 100);     
        setDefaultCloseOperation(EXIT_ON_CLOSE);     
      
        setupComponents();     
    }     
      
    // 初始化控件     
    private void setupComponents() {     
        setupBorder();     
      
        JPanel topPanel = new JPanel(new BorderLayout(5, 0));     
        this.add(topPanel, BorderLayout.NORTH);     
        setupTopPanel(topPanel);     
      
        JPanel centerPanel = new JPanel(new BorderLayout());     
        this.add(centerPanel, BorderLayout.CENTER);     
        setupCenterPanel(centerPanel);     
    }     
      
    // 给窗体面板加上边框     
    private void setupBorder() {     
        JPanel panel = new JPanel(new BorderLayout(5, 5));     
        panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));     
        this.setContentPane(panel);     
    }     
      
    // 文本域面板     
    private void setupCenterPanel(JPanel panel) {     
        textarea.setFont(new Font(Font.DIALOG_INPUT, 0, 12));     
        panel.add(new JScrollPane(textarea));     
    }     
      
    // 上方面板     
    private void setupTopPanel(JPanel panel) {     
        textbox.setFont(new Font(Font.DIALOG_INPUT, 0, 12));     
        panel.add(textbox, BorderLayout.CENTER);     
      
        JButton button = new JButton("测试");     
        button.addActionListener(new ActionListener() {     
            public void actionPerformed(ActionEvent e) {     
                checkRegularExpression();     
            }     
        });     
        panel.add(button, BorderLayout.EAST);     
        panel.add(new JLabel("正则表达式："), BorderLayout.WEST);     
    }     
      
    // 检查正则表达式     
    private void checkRegularExpression() {     
        textarea.getHighlighter().removeAllHighlights();     
      
        String reg = textbox.getText();     
        String text = textarea.getText();     
      
        Pattern p = Pattern.compile(reg);     
        Matcher m = p.matcher(text);     
        if (m.find()) {     
            thisFrame.setTitle("文本符合表达式。");     
            highlightMatches(m);     
        } else {     
            thisFrame.setTitle("文本不符合表达式。");     
        }     
    }     
      
    // 将符合正则表达式的部分高亮显示     
    private void highlightMatches(Matcher m) {     
        highlight(m);     
        int start = m.end();     
        while (m.find(start)) {     
            highlight(m);     
            start = m.end();     
        }     
    }     
      
    private void highlight(Matcher m) {     
        try {     
            textarea.getHighlighter().addHighlight(m.start(), m.end(), highlightPainter);     
        } catch (BadLocationException e) {     
            e.printStackTrace();     
        }     
    }     
}