扩展JTextPane,使其有关键字自动加亮功能。

import java.util.StringTokenizer;

import java.awt.*;import java.awt.event.*;

import javax.swing.*;import javax.swing.text.*;import javax.swing.event.*;import javax.swing.text.rtf.RTFEditorKit;

public class MyTextPane extends JTextPane {

    protected StyleContext m_context;    protected DefaultStyledDocument m_doc;    private   MutableAttributeSet keyAttr,normalAttr;    private   MutableAttributeSet inputAttributes =                new RTFEditorKit().getInputAttributes();

 private String[] keyWord={"SELECT","FROM","WHERE"};

    public MyTextPane() {        super();        m_context = new StyleContext();        m_doc = new DefaultStyledDocument(m_context);        this.setDocument(m_doc);

        this.addKeyListener(new KeyAdapter() {            public void keyReleased(KeyEvent ke) {                syntaxParse();            }        });

  file://定义关键字显示属性        keyAttr = new SimpleAttributeSet();        StyleConstants.setForeground(keyAttr, Color.blue);

  file://定义一般文本显示属性        normalAttr = new SimpleAttributeSet();        StyleConstants.setForeground(normalAttr, Color.black);    }

    public void syntaxParse() {        try {            String s = null;            Element root = m_doc.getDefaultRootElement();file://取光标当前行            int cursorPos = this.getCaretPosition();    file://当前光标的位置            int line = root.getElementIndex(cursorPos); file://取当前行

            Element para = root.getElement(line);            int start = para.getStartOffset();            int end = para.getEndOffset() - 1; file://删除/r字符            s = m_doc.getText(start, end - start).toUpperCase();

            int i = 0;            int xStart = 0;

file://分析关键字---            m_doc.setCharacterAttributes(start, s.length(),normalAttr, false);            MyStringTokenizer st = new MyStringTokenizer(s);            while( st.hasMoreTokens()) {                s = st.nextToken();                if ( s == null) return;                for (i = 0; i < keyWord.length; i++ ) {                    if (s.equals(keyWord[i])) break;                }                if ( i >= keyWord.length ) continue;

                xStart = st.getCurrPosition();

                file://设置关键字显示属性                m_doc.setCharacterAttributes(start+xStart, s.length(),                                             keyAttr, false);            }            inputAttributes.addAttributes(normalAttr);        } catch (Exception ex) {            ex.printStackTrace();        }    }

    public static void main(String[] args) {        JFrame frame = new JFrame("test text pane");        frame.getContentPane().add(new MyTextPane());        WindowListener wndCloser = new WindowAdapter() {            public void windowClosing(WindowEvent e) {                System.exit(0);            }        };        frame.addWindowListener(wndCloser);        final int inset = 50;        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();        frame.setBounds ( inset, inset, screenSize.width - inset*2, screenSize.height - inset*2 );        frame.show();    }}

/*在分析字符串的同时，记录每个token所在的位置**/class MyStringTokenizer extends StringTokenizer{    String sval = " ";    String oldStr,str;    int m_currPosition = 0,m_beginPosition=0;    MyStringTokenizer(String str) {        super(str," ");        this.oldStr = str;        this.str = str;    }

    public String nextToken() {       try {           String s = super.nextToken();           int pos = -1;

           if (oldStr.equals(s)) {               return s;           }

           pos = str.indexOf(s + sval);           if ( pos == -1) {               pos = str.indexOf(sval + s);               if ( pos == -1)                   return null;               else pos += 1;           }

           int xBegin = pos + s.length();           str = str.substring(xBegin);

           m_currPosition = m_beginPosition + pos;           m_beginPosition = m_beginPosition + xBegin;           return s;       } catch (java.util.NoSuchElementException ex) {           ex.printStackTrace();           return null;       }    }

   file://返回token在字符串中的位置   public int getCurrPosition() {       return m_currPosition;   }}