JTextPane Java关键字变色

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={"int","float"};

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();
}
});

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

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

public void syntaxParse() {
try {
String s = null;
Element root = m_doc.getDefaultRootElement();

int cursorPos = this.getCaretPosition();
int line = root.getElementIndex(cursorPos);

Element para = root.getElement(line);
int start = para.getStartOffset();
int end = para.getEndOffset() - 1;
s = m_doc.getText(start, end - start);

int i = 0;
int xStart = 0;

//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();

//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;
}
}

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