大约10年前（或更多），我试图做到这一点（为了好玩）。由于代码太旧，我不记得代码中的所有细节和代码中的逻辑条件。这里的所有代码基本上都是一个强力解决方案。它决不会试图保持rici所建议的每条线的状态。
我会尽力解释代码的高级概念。希望其中的一些对你有意义。
目前它每次用户输入单个字符时都会简单地解析并突出显示当前行。
这也是我的代码的基本前提。但是，它也处理粘贴多行代码。
如何在保持效率的同时在语法高亮显示中处理多行标记/注释？
在我的解决方案，当你进入"/*"启动多行注释，我会评论的代码下面所有的行，直到我找到注释的结尾或另一个多行注释的开始或文档的结尾。当您输入匹配的"*/"以结束多行注释时，我将重新突出显示以下行，直到下一个多行注释或文档结束。
因此，突出显示的数量取决于多行注释之间的代码量。
这是它如何工作的快速概述。我怀疑这是100％准确的，因为我只玩过一点点。应该指出，这段代码是在我刚刚学习Java时编写的，所以我绝不会认为这是最好的方法，只是我当时知道的最好的方法。
这里是您娱乐:)
只要运行该代码，并点击按钮即可开始的代码。
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
class SyntaxDocument extends DefaultStyledDocument
{
private DefaultStyledDocument doc;
private Element rootElement;
private boolean multiLineComment;
private MutableAttributeSet normal;
private MutableAttributeSet keyword;
private MutableAttributeSet comment;
private MutableAttributeSet quote;
private Set<String> keywords;
private int lastLineProcessed = -1;
public SyntaxDocument()
{
doc = this;
rootElement = doc.getDefaultRootElement();
putProperty(DefaultEditorKit.EndOfLineStringProperty, "\n");
normal = new SimpleAttributeSet();
StyleConstants.setForeground(normal, Color.black);
comment = new SimpleAttributeSet();
StyleConstants.setForeground(comment, Color.gray);
StyleConstants.setItalic(comment, true);
keyword = new SimpleAttributeSet();
StyleConstants.setForeground(keyword, Color.blue);
quote = new SimpleAttributeSet();
StyleConstants.setForeground(quote, Color.red);
keywords = new HashSet<String>();
keywords.add("abstract");
keywords.add("boolean");
keywords.add("break");
keywords.add("byte");
keywords.add("byvalue");
keywords.add("case");
keywords.add("cast");
keywords.add("catch");
keywords.add("char");
keywords.add("class");
keywords.add("const");
keywords.add("continue");
keywords.add("default");
keywords.add("do");
keywords.add("double");
keywords.add("else");
keywords.add("extends");
keywords.add("false");
keywords.add("final");
keywords.add("finally");
keywords.add("float");
keywords.add("for");
keywords.add("future");
keywords.add("generic");
keywords.add("goto");
keywords.add("if");
keywords.add("implements");
keywords.add("import");
keywords.add("inner");
keywords.add("instanceof");
keywords.add("int");
keywords.add("interface");
keywords.add("long");
keywords.add("native");
keywords.add("new");
keywords.add("null");
keywords.add("operator");
keywords.add("outer");
keywords.add("package");
keywords.add("private");
keywords.add("protected");
keywords.add("public");
keywords.add("rest");
keywords.add("return");
keywords.add("short");
keywords.add("static");
keywords.add("super");
keywords.add("switch");
keywords.add("synchronized");
keywords.add("this");
keywords.add("throw");
keywords.add("throws");
keywords.add("transient");
keywords.add("true");
keywords.add("try");
keywords.add("var");
keywords.add("void");
keywords.add("volatile");
keywords.add("while");
}
/*
* Override to apply syntax highlighting after the document has been updated
*/
public void insertString(int offset, String str, AttributeSet a) throws BadLocationException
{
if (str.equals("{"))
str = addMatchingBrace(offset);
super.insertString(offset, str, a);
processChangedLines(offset, str.length());
}
/*
* Override to apply syntax highlighting after the document has been updated
*/
public void remove(int offset, int length) throws BadLocationException
{
super.remove(offset, length);
processChangedLines(offset, 0);
}
/*
* Determine how many lines have been changed,
* then apply highlighting to each line
*/
public void processChangedLines(int offset, int length)
throws BadLocationException
{
String content = doc.getText(0, doc.getLength());
// The lines affected by the latest document update
int startLine = rootElement.getElementIndex(offset);
int endLine = rootElement.getElementIndex(offset + length);
if (startLine > endLine)
startLine = endLine;
// Make sure all comment lines prior to the start line are commented
// and determine if the start line is still in a multi line comment
if (startLine != lastLineProcessed
&& startLine != lastLineProcessed + 1)
{
setMultiLineComment(commentLinesBefore(content, startLine));
}
// Do the actual highlighting
for (int i = startLine; i <= endLine; i++)
{
applyHighlighting(content, i);
}
// Resolve highlighting to the next end multi line delimiter
if (isMultiLineComment())
commentLinesAfter(content, endLine);
else
highlightLinesAfter(content, endLine);
}
/*
* Highlight lines when a multi line comment is still 'open'
* (ie. matching end delimiter has not yet been encountered)
*/
private boolean commentLinesBefore(String content, int line)
{
int offset = rootElement.getElement(line).getStartOffset();
// Start of comment not found, nothing to do
int startDelimiter = lastIndexOf(content, getStartDelimiter(), offset - 2);
if (startDelimiter < 0)
return false;
// Matching start/end of comment found, nothing to do
int endDelimiter = indexOf(content, getEndDelimiter(), startDelimiter);
if (endDelimiter < offset & endDelimiter != -1)
return false;
// End of comment not found, highlight the lines
doc.setCharacterAttributes(startDelimiter, offset - startDelimiter + 1, comment, false);
return true;
}
/*
* Highlight comment lines to matching end delimiter
*/
private void commentLinesAfter(String content, int line)
{
int offset = rootElement.getElement(line).getStartOffset();
// End of comment and Start of comment not found
// highlight until the end of the Document
int endDelimiter = indexOf(content, getEndDelimiter(), offset);
if (endDelimiter < 0)
{
endDelimiter = indexOf(content, getStartDelimiter(), offset + 2);
if (endDelimiter < 0)
{
doc.setCharacterAttributes(offset, content.length() - offset + 1, comment, false);
return;
}
}
// Matching start/end of comment found, comment the lines
int startDelimiter = lastIndexOf(content, getStartDelimiter(), endDelimiter);
if (startDelimiter < 0 || startDelimiter >= offset)
{
doc.setCharacterAttributes(offset, endDelimiter - offset + 1, comment, false);
}
}
/*
* Highlight lines to start or end delimiter
*/
private void highlightLinesAfter(String content, int line)
throws BadLocationException
{
int offset = rootElement.getElement(line).getEndOffset();
// Start/End delimiter not found, nothing to do
int startDelimiter = indexOf(content, getStartDelimiter(), offset);
int endDelimiter = indexOf(content, getEndDelimiter(), offset);
if (startDelimiter < 0)
startDelimiter = content.length();
if (endDelimiter < 0)
endDelimiter = content.length();
int delimiter = Math.min(startDelimiter, endDelimiter);
if (delimiter < offset)
return;
// Start/End delimiter found, reapply highlighting
int endLine = rootElement.getElementIndex(delimiter);
for (int i = line + 1; i <= endLine; i++)
{
Element branch = rootElement.getElement(i);
Element leaf = doc.getCharacterElement(branch.getStartOffset());
AttributeSet as = leaf.getAttributes();
if (as.isEqual(comment))
{
applyHighlighting(content, i);
}
}
}
/*
* Parse the line to determine the appropriate highlighting
*/
private void applyHighlighting(String content, int line)
throws BadLocationException
{
lastLineProcessed = line;
int startOffset = rootElement.getElement(line).getStartOffset();
int endOffset = rootElement.getElement(line).getEndOffset() - 1;
int lineLength = endOffset - startOffset;
int contentLength = content.length();
if (endOffset >= contentLength)
endOffset = contentLength - 1;
// check for multi line comments
// (always set the comment attribute for the entire line)
if (endingMultiLineComment(content, startOffset, endOffset)
|| isMultiLineComment()
|| startingMultiLineComment(content, startOffset, endOffset))
{
doc.setCharacterAttributes(startOffset, endOffset - startOffset + 1, comment, false);
lastLineProcessed = -1;
return;
}
// set normal attributes for the line
doc.setCharacterAttributes(startOffset, lineLength, normal, true);
// check for single line comment
int index = content.indexOf(getSingleLineDelimiter(), startOffset);
if ((index > -1) && (index < endOffset))
{
doc.setCharacterAttributes(index, endOffset - index + 1, comment, false);
endOffset = index - 1;
}
// check for tokens
checkForTokens(content, startOffset, endOffset);
}
/*
* Does this line contain the start delimiter
*/
private boolean startingMultiLineComment(String content, int startOffset, int endOffset)
throws BadLocationException
{
int index = indexOf(content, getStartDelimiter(), startOffset);
if ((index < 0) || (index > endOffset))
return false;
else
{
setMultiLineComment(true);
return true;
}
}
/*
* Does this line contain the end delimiter
*/
private boolean endingMultiLineComment(String content, int startOffset, int endOffset)
throws BadLocationException
{
int index = indexOf(content, getEndDelimiter(), startOffset);
if ((index < 0) || (index > endOffset))
return false;
else
{
setMultiLineComment(false);
return true;
}
}
/*
* We have found a start delimiter
* and are still searching for the end delimiter
*/
private boolean isMultiLineComment()
{
return multiLineComment;
}
private void setMultiLineComment(boolean value)
{
multiLineComment = value;
}
/*
* Parse the line for tokens to highlight
*/
private void checkForTokens(String content, int startOffset, int endOffset)
{
while (startOffset <= endOffset)
{
// skip the delimiters to find the start of a new token
while (isDelimiter(content.substring(startOffset, startOffset + 1)))
{
if (startOffset < endOffset)
startOffset++;
else
return;
}
// Extract and process the entire token
if (isQuoteDelimiter(content.substring(startOffset, startOffset + 1)))
startOffset = getQuoteToken(content, startOffset, endOffset);
else
startOffset = getOtherToken(content, startOffset, endOffset);
}
}
/*
*
*/
private int getQuoteToken(String content, int startOffset, int endOffset)
{
String quoteDelimiter = content.substring(startOffset, startOffset + 1);
String escapeString = getEscapeString(quoteDelimiter);
int index;
int endOfQuote = startOffset;
// skip over the escape quotes in this quote
index = content.indexOf(escapeString, endOfQuote + 1);
while ((index > -1) && (index < endOffset))
{
endOfQuote = index + 1;
index = content.indexOf(escapeString, endOfQuote);
}
// now find the matching delimiter
index = content.indexOf(quoteDelimiter, endOfQuote + 1);
if ((index < 0) || (index > endOffset))
endOfQuote = endOffset;
else
endOfQuote = index;
doc.setCharacterAttributes(startOffset, endOfQuote - startOffset + 1, quote, false);
return endOfQuote + 1;
}
/*
*
*/
private int getOtherToken(String content, int startOffset, int endOffset)
{
int endOfToken = startOffset + 1;
while (endOfToken <= endOffset)
{
if (isDelimiter(content.substring(endOfToken, endOfToken + 1)))
break;
endOfToken++;
}
String token = content.substring(startOffset, endOfToken);
if (isKeyword(token))
{
doc.setCharacterAttributes(startOffset, endOfToken - startOffset, keyword, false);
}
return endOfToken + 1;
}
/*
* Assume the needle will be found at the start/end of the line
*/
private int indexOf(String content, String needle, int offset)
{
int index;
while ((index = content.indexOf(needle, offset)) != -1)
{
String text = getLine(content, index).trim();
if (text.startsWith(needle) || text.endsWith(needle))
break;
else
offset = index + 1;
}
return index;
}
/*
* Assume the needle will the found at the start/end of the line
*/
private int lastIndexOf(String content, String needle, int offset)
{
int index;
while ((index = content.lastIndexOf(needle, offset)) != -1)
{
String text = getLine(content, index).trim();
if (text.startsWith(needle) || text.endsWith(needle))
break;
else
offset = index - 1;
}
return index;
}
private String getLine(String content, int offset)
{
int line = rootElement.getElementIndex(offset);
Element lineElement = rootElement.getElement(line);
int start = lineElement.getStartOffset();
int end = lineElement.getEndOffset();
return content.substring(start, end - 1);
}
/*
* Override for other languages
*/
protected boolean isDelimiter(String character)
{
String operands = ";:{}()[]+-/%<=>!&|^~*";
if (Character.isWhitespace(character.charAt(0))
|| operands.indexOf(character) != -1)
return true;
else
return false;
}
/*
* Override for other languages
*/
protected boolean isQuoteDelimiter(String character)
{
String quoteDelimiters = "\"'";
if (quoteDelimiters.indexOf(character) < 0)
return false;
else
return true;
}
/*
* Override for other languages
*/
protected boolean isKeyword(String token)
{
return keywords.contains(token);
}
/*
* Override for other languages
*/
protected String getStartDelimiter()
{
return "/*";
}
/*
* Override for other languages
*/
protected String getEndDelimiter()
{
return "*/";
}
/*
* Override for other languages
*/
protected String getSingleLineDelimiter()
{
return "//";
}
/*
* Override for other languages
*/
protected String getEscapeString(String quoteDelimiter)
{
return "\\" + quoteDelimiter;
}
/*
*
*/
protected String addMatchingBrace(int offset) throws BadLocationException
{
StringBuffer whiteSpace = new StringBuffer();
int line = rootElement.getElementIndex(offset);
int i = rootElement.getElement(line).getStartOffset();
while (true)
{
String temp = doc.getText(i, 1);
if (temp.equals(" ") || temp.equals("\t"))
{
whiteSpace.append(temp);
i++;
}
else
break;
}
return "{\n" + whiteSpace.toString() + "\t\n" + whiteSpace.toString() + "}";
}
/*
public void setCharacterAttributes(int offset, int length, AttributeSet s, boolean replace)
{
super.setCharacterAttributes(offset, length, s, replace);
}
*/
public static void main(String a[])
{
EditorKit editorKit = new StyledEditorKit()
{
public Document createDefaultDocument()
{
return new SyntaxDocument();
}
};
// final JEditorPane edit = new JEditorPane()
final JTextPane edit = new JTextPane();
// LinePainter painter = new LinePainter(edit, Color.cyan);
// LinePainter2 painter = new LinePainter2(edit, Color.cyan);
// edit.setEditorKitForContentType("text/java", editorKit);
// edit.setContentType("text/java");
edit.setEditorKit(editorKit);
JButton button = new JButton("Load SyntaxDocument.java");
button.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
try
{
long startTime = System.currentTimeMillis();
FileReader fr = new FileReader("SyntaxDocument.java");
// FileReader fr = new FileReader("C:\\Java\\j2sdk1.4.2\\src\\javax\\swing\\JComponent.java");
BufferedReader br = new BufferedReader(fr);
edit.read(br, null);
System.out.println("Load: " + (System.currentTimeMillis() - startTime));
System.out.println("Document contains: " + edit.getDocument().getLength() + " characters");
edit.requestFocus();
}
catch(Exception e2) {}
}
});
JFrame frame = new JFrame("Syntax Highlighting");
frame.getContentPane().add(new JScrollPane(edit));
frame.getContentPane().add(button, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800,300);
frame.setVisible(true);
}
}
注意：此代码不检查注释分隔符是否在文字内，因此需要对其进行改进。
我并不真的希望你使用这段代码，但我认为这可能会让你了解使用暴力方法时可能获得的性能。