处理文章截取时对html的处理

package people.util;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.log4j.Logger;

public class CutHtml extends TagSupport {

    private static final long serialVersionUID = 1L;
    protected final Logger log = Logger.getLogger(getClass());

    private static String htmlMatch = "";
    private String param;
    private int length;
    private String endWith;

    public int doStartTag() throws JspException {
JspWriter out = pageContext.getOut();
String str = null;
try {
    str = subStringHTML(param, length, endWith);
    str=str.replaceAll("<img", "<img onload=\"javascript:DrawImage(this,200,150)\"");
    str=str.replaceAll("<IMG", "<IMG onload=\"javascript:DrawImage(this,200,150)\"");
    out.print(str);
} catch (Exception e) {
    log.error("", e);
}
return super.doStartTag();
    }

    // 通过递归删除html文件中的配对的html标签

    public static String removeMatchHtmlTag() {

Pattern p = Pattern.compile("<([a-zA-Z]+)[^<>]*>(.*?)</\\1>");
Matcher m = p.matcher(htmlMatch);

if (m.find()) {

    htmlMatch = htmlMatch.replaceAll("<([a-zA-Z]+)[^<>]*>(.*?)</\\1>", "$2");

    removeMatchHtmlTag();
}

return htmlMatch;
    }

    public static String subStringHTML(String par, int len, String end) {

if (len < 1) {

    return null;
}

if (par.length() < len) {
    return par;
}

StringBuffer result = new StringBuffer();
StringBuffer str = new StringBuffer();
int n = 0;

char temp;

boolean isCode = false; // 是不是HTML代码
boolean isHTML = false; // 是不是HTML特殊字符,如
for (int i = 0; i < par.length(); i++) {
    temp = par.charAt(i);
    if (temp == '<') {
isCode = true;
    } else if (temp == '&') {
isHTML = true;
    } else if (temp == '>' && isCode) {
n = n - 1;
isCode = false;
    } else if (temp == ';' && isHTML) {
isHTML = false;
    }
    if (!isCode && !isHTML) {
n = n + 1;
if ((temp + "").getBytes().length > 1) {
    n = n + 1;
}
str.append(temp);
    }
    result.append(temp);
    if (n >= len) {
break;
    }
}

result.append(end);
// 取出截取字符串中的HTML标记
String temp_result = result.toString().replaceAll("(>)[^<>]*(<?)", "$1$2");

// 去掉不需要结束标记的HTML标记

temp_result = temp_result
.replaceAll(
"<(AREA|BASE|BASEFONT|BODY|BR|COL|COLGROUP|DD|DT|FRAME|HEAD|HR|HTML|IMG|INPUT|ISINDEX|LI|LINK|META|OPTION|P|PARAM|TBODY|TD|TFOOT|TH|THEAD|TR|area|base|basefont|body|br|col|colgroup|dd|dt|frame|head|hr|html|img|input|isindex|li|link|meta|option|p|param|tbody|td|tfoot|th|thead|tr)[^<>]*/>",
"");

// 去掉成对的HTML标记
htmlMatch = temp_result;
temp_result = removeMatchHtmlTag();

// 用正则表达式取出标记

Pattern p = Pattern.compile("<([a-zA-Z]+)[^<>]*>");
Matcher m = p.matcher(temp_result);
List<String> endHTML = new ArrayList<String>();

while (m.find()) {
    endHTML.add(m.group(1));
}

// 补全不成对的HTML标记
for (int i = endHTML.size() - 1; i >= 0; i--) {
    result.append("</");
    result.append(endHTML.get(i));
    result.append(">");
}
return result.toString();

    }

    public String getParam() {
return param;
    }

    public void setParam(String param) {
this.param = param;
    }

    public int getLength() {
return length;
    }

    public void setLength(int length) {
this.length = length;
    }

    public String getEndWith() {
return endWith;
    }

    public void setEndWith(String endWith) {
this.endWith = endWith;
    }

}