如何在 Swing 的 JTextArea 中执行正则表达式

Question

我想用给定的正则表达式替换所有匹配的单词。我为此编写了代码。但是，它只是替换它，但没有执行特定的操作。当我选择正则表达式然后我点击全部替换，它会替换为特定操作，而不是替换为给定的字符串/字符。 例如我的输入是“\n”，匹配的字符串/字符替换为换行操作，而不是替换换行符。请检查并帮助我。谢谢。 我的代码：

public class RegularExp extends javax.swing.JFrame {
JTextArea text;
int i=0;
UndoManager undoManager = new UndoManager();
public RegularExp() {
    initComponents();
    text = new JTextArea();
    replace.setEnabled(false);
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    tp = new javax.swing.JTabbedPane();
    jMenuBar1 = new javax.swing.JMenuBar();
    fileMenu = new javax.swing.JMenu();
    open = new javax.swing.JMenuItem();
    replace = new javax.swing.JMenuItem();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    fileMenu.setText("File");

    open.setText("Open");
    open.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            openActionPerformed(evt);
        }
    });
    fileMenu.add(open);

    replace.setText("Replace");
    replace.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            replaceActionPerformed(evt);
        }
    });
    fileMenu.add(replace);

    jMenuBar1.add(fileMenu);

    setJMenuBar(jMenuBar1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>                        

private void replaceActionPerformed(java.awt.event.ActionEvent evt) {                                        
    JDialog replace_dialog=new JDialog(RegularExp.this);
    replace_dialog.setTitle("Replace");
    JLabel find_label=new JLabel("Find what");
    final JTextField find_tf=new JTextField(10);
    JLabel replace_label=new JLabel("Replace With");
    final JTextField replace_tf=new JTextField(10);
    final JCheckBox regx=new JCheckBox("Regular Expression");
    JButton replaceAll=new JButton("Replace All");
    replace_dialog.setLayout(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();
    c.insets = new Insets(5, 5, 5, 5);
    c.gridx = 0;
    c.gridy = 0;
    c.anchor = GridBagConstraints.WEST;
    replace_dialog.add(find_label, c);
    c.gridx++;
    c.fill = GridBagConstraints.HORIZONTAL;
    c.weightx = 1;
    replace_dialog.add(find_tf, c);
    c.gridx = 0;
    c.gridy = 1;
    c.gridwidth = 2;
    replace_dialog.add(replace_label, c);
    c.gridx++;
    c.fill = GridBagConstraints.HORIZONTAL;
    c.weightx = 1;
    replace_dialog.add(replace_tf, c);
    c.gridx++;
    c.gridx++;
    c.gridwidth = 1;
    c.fill = GridBagConstraints.HORIZONTAL;
    replace_dialog.add(replaceAll, c);
    c.gridx=0;
    c.gridy++;
    c.gridwidth = 1;
    c.fill = GridBagConstraints.HORIZONTAL;
    replace_dialog.add(regx, c);
    replace_dialog.setSize(400,400);
    replace_dialog.setLocationRelativeTo(null);
    replace_dialog.pack();
    replace_dialog.setVisible(true);
    replaceAll.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            if(regx.isSelected()){
                int caret_pos=text.getCaretPosition();
                text.setText(text.getText().replaceAll(find_tf.getText(),"\\"+ replace_tf.getText()));
                text.setCaretPosition(caret_pos);
            }    
            else {
                int caret_pos=text.getCaretPosition();
                text.setText(text.getText().replaceAll(find_tf.getText(), replace_tf.getText()));
                text.setCaretPosition(caret_pos);
            }
        }
    });
}                                       

private void openActionPerformed(java.awt.event.ActionEvent evt) {                                     
    final JFileChooser jc = new JFileChooser();
    int returnVal=  jc.showOpenDialog(RegularExp.this);
    String title;
    File file=null;
    if(returnVal == JFileChooser.APPROVE_OPTION)
    file = jc.getSelectedFile();
    if (jc.getSelectedFile()!= null) {
        BufferedReader br = null;
        StringBuffer str = new StringBuffer("");
        try {
            br = new BufferedReader(new FileReader(file));
            String line;
            while ((line = br.readLine()) != null) {
                str.append(line + "\n");
            }
        }
        catch (IOException ex) {
            Logger.getLogger(RegularExp.class.getName()).log(Level.SEVERE, null, ex);
        }
        String t = str.toString();
        final JInternalFrame internalFrame = new JInternalFrame("",true,true);
        title=file.getName();
        text.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
        internalFrame.add(text);
        i+=1;
        internalFrame.setName("Doc "+i);
        JScrollPane scrollpane=new JScrollPane(text);
        internalFrame.setTitle(title);
        tp.add(internalFrame);
        internalFrame.add(scrollpane);
        internalFrame.setVisible(true);
        text.setText(t);
        text.setCaretPosition(0);
        replace.setEnabled(true);
    }
}                                    

public static void main(String args[]) {
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(RegularExp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(RegularExp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(RegularExp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(RegularExp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new RegularExp().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JMenu fileMenu;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem open;
private javax.swing.JMenuItem replace;
private javax.swing.JTabbedPane tp;
// End of variables declaration                   
}

Answer 1

重点是：在其中一种情况下，您应该使用函数replace() 而不是replaceAll()。

请注意，replace() 和 replaceAll() 函数都会替换所有匹配项。它们之间的唯一区别是replaceAll() 使用正则表达式，而replace() 不使用。

所以你应该使用以下代码：

replaceAll.addActionListener(new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e){
        int caret_pos = text.getCaretPosition();
        if(regx.isSelected()){
            text.setText(text.getText().replaceAll(
                    find_tf.getText(), replace_tf.getText()));
        }
        else{
            text.setText(text.getText().replace(
                    find_tf.getText(), replace_tf.getText()));
        }
        text.setCaretPosition(Math.min(caret_pos,text.getText().length()));
    }
});

---

根据您的 cmets，您的问题与正则表达式无关。您只想在两种情况下以不同的方式处理 \n 和 \t 等特殊字符。我会让上面的解释给那些真正想使用正则表达式的人。另外，我将在下面添加您的具体情况的答案。

更新的答案适用于您在评论中描述的两种情况：

replaceAll.addActionListener(new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e){
        int caret_pos = text.getCaretPosition();
        if(regx.isSelected()){
            text.setText(text.getText().replace(
                    find_tf.getText().replace("\\n","\n").replace("\\t","\t"),
                    replace_tf.getText().replace("\\n","\n").replace("\\t","\t")));
        }
        else{
            text.setText(text.getText().replace(
                    find_tf.getText(),
                    replace_tf.getText()));
        }
        text.setCaretPosition(Math.min(caret_pos,text.getText().length()));
    }
});

此代码处理\n 和\t。如果您想处理其他特殊字符，您只需添加其他替换。例如：如果要处理\r，则需要以下代码：

text.setText(text.getText().replace(
        find_tf.getText().replace("\\n","\n").replace("\\t","\t").replace("\\r","\r"),
        replace_tf.getText().replace("\\n","\n").replace("\\t","\t").replace("\\r","\r")));

您可以在此处获得所有 JAVA 转义序列的列表：http://docs.oracle.com/javase/tutorial/java/data/characters.html

• \t此时在文本中插入一个制表符。
• \b此时在文本中插入一个退格键。
• \n此时在文本中插入换行符。
• \r此时在文本中插入回车。
• \f 此时在文本中插入换页符。
• \'此时在文本中插入一个单引号字符。
• \"此时在文本中插入双引号字符。
• \\此时在文本中插入一个反斜杠字符。