Java正则表达式过滤html标签

import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* <p>
* Title: HTML相关的正则表达式工具类
* </p>
* <p>
* Description: 包括过滤HTML标记，转换HTML标记，替换特定HTML标记
* </p>
* <p>
* Copyright: Copyright (c) 2006
* </p>
*
* @author hejian
* @version 1.0
* @createtime 2006-10-16
*/
public class HtmlRegexpUtil {
private final static String regxpForHtml = "<([^>]*)>"; // 过滤所有以<开头以>结尾的标签
private final static String regxpForImgTag = "<\\s*img\\s+([^>]*)\\s*>"; // 找出IMG标签
private final static String regxpForImaTagSrcAttrib = "src=\"([^\"]+)\""; // 找出IMG标签的SRC属性
/**
*
*/
public HtmlRegexpUtil() {
// TODO Auto-generated constructor stub
}
/**
*
* 基本功能：替换标记以正常显示
* <p>
*
* @param input
* @return String
*/
public String replaceTag(String input) {
if (!hasSpecialChars(input)) {
return input;
}
StringBuffer filtered = new StringBuffer(input.length());
char c;
for (int i = 0; i <= input.length() - 1; i++) {
c = input.charAt(i);
switch (c) {
case '<':
filtered.append("&lt;");
break;
case '>':
filtered.append("&gt;");
break;
case '"':
filtered.append("&quot;");
break;
case '&':
filtered.append("&amp;");
break;
default:
filtered.append(c);
}
}
return (filtered.toString());
}
/**
*
* 基本功能：判断标记是否存在
* <p>
*
* @param input
* @return boolean
*/
public boolean hasSpecialChars(String input) {
boolean flag = false;
if ((input != null) && (input.length() > 0)) {
char c;
for (int i = 0; i <= input.length() - 1; i++) {
c = input.charAt(i);
switch (c) {
case '>':
flag = true;
break;
case '<':
flag = true;
break;
case '"':
flag = true;
break;
case '&':
flag = true;
break;
}
}
}
return flag;
}
 
/**
*
* 基本功能：过滤所有以"<"开头以">"结尾的标签
* <p>
*
* @param str
* @return String
*/
public static String filterHtml(String str) {
Pattern pattern = Pattern.compile(regxpForHtml);
Matcher matcher = pattern.matcher(str);
StringBuffer sb = new StringBuffer();
boolean result1 = matcher.find();
while (result1) {
matcher.appendReplacement(sb, "");
result1 = matcher.find();
}
matcher.appendTail(sb);
return sb.toString();
}
/**
*
* 基本功能：过滤指定标签
* <p>
*
* @param str
* @param tag
*            指定标签
* @return String
*/
public static String fiterHtmlTag(String str, String tag) {
String regxp = "<\\s*" + tag + "\\s+([^>]*)\\s*>";
Pattern pattern = Pattern.compile(regxp);
Matcher matcher = pattern.matcher(str);
StringBuffer sb = new StringBuffer();
boolean result1 = matcher.find();
while (result1) {
matcher.appendReplacement(sb, "");
result1 = matcher.find();
}
matcher.appendTail(sb);
return sb.toString();
}
/**
*
* 基本功能：替换指定的标签
* <p>
*
* @param str
* @param beforeTag
*            要替换的标签
* @param tagAttrib
*            要替换的标签属性值
* @param startTag
*            新标签开始标记
* @param endTag
*            新标签结束标记
* @return String
* @如：替换img标签的src属性值为[img]属性值[/img]
*/
public static String replaceHtmlTag(String str, String beforeTag,
String tagAttrib, String startTag, String endTag) {
String regxpForTag = "<\\s*" + beforeTag + "\\s+([^>]*)\\s*>";
String regxpForTagAttrib = tagAttrib + "=\"([^\"]+)\"";
Pattern patternForTag = Pattern.compile(regxpForTag);
Pattern patternForAttrib = Pattern.compile(regxpForTagAttrib);
Matcher matcherForTag = patternForTag.matcher(str);
StringBuffer sb = new StringBuffer();
boolean result = matcherForTag.find();
while (result) {
StringBuffer sbreplace = new StringBuffer();
Matcher matcherForAttrib = patternForAttrib.matcher(matcherForTag
.group(1));
if (matcherForAttrib.find()) {
matcherForAttrib.appendReplacement(sbreplace, startTag
+ matcherForAttrib.group(1) + endTag);
}
matcherForTag.appendReplacement(sb, sbreplace.toString());
result = matcherForTag.find();
}
matcherForTag.appendTail(sb);
return sb.toString();
}
}