java面包屑导航制作

做了个简单的面包屑导航功能,比如页面上大家经常看到的这种导航： 
 
您所在的位置：音乐社区-->用户模块-->用户注册 
 
我做成了标签的形式，利用jom4j来解析xml文件：
 
核心类SiteMapTag.java： 

Java代码  
 

package com.market.common;import java.io.InputStream;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import javax.servlet.http.HttpServletRequest;import javax.servlet.jsp.JspException;import javax.servlet.jsp.tagext.TagSupport;import org.dom4j.Attribute;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;/** * 站点导航标签的实现  * <p> * Title: SiteMapTag.java * </p> * <p> * Description: * </p> * <p> * Copyright: Copyright (c) 2012 * </p> *  * @author  fjs * @version   Sep 15, 2012 */public class SiteMapTag extends TagSupport {private static final long serialVersionUID = -3531938467909884528L;private String currentFilePath;private Element target;@Overridepublic int doStartTag() throws JspException {HttpServletRequest request = (HttpServletRequest) this.pageContext.getRequest();currentFilePath = request.getRequestURI().replaceFirst(request.getContextPath(), "");try {Element root = (Element)pageContext.getServletContext().getAttribute("webSiteMapSet");if(root==null){SAXReader reader = new SAXReader();InputStream inputStream = SiteMapTag.class.getClassLoader().getResourceAsStream("sitemap.xml");Document document = reader.read(inputStream);root = document.getRootElement();pageContext.getServletContext().setAttribute("webSiteMapSet", root);}parseParent(root);StringBuffer content = new StringBuffer("");List<String> titles = new ArrayList<String>();List<String> hrefs = new ArrayList<String>();while(target!=null){Attribute attTitle = target.attribute("title");if(attTitle!=null){titles.add(attTitle.getText());}Attribute attHref = target.attribute("href");if(attHref!=null){hrefs.add(attHref.getText());}else{hrefs.add("");}target = target.getParent();}for (int i = titles.size()-1; i >=0; i--) {String href = hrefs.get(i);if(href.equals("")){content.append(titles.get(i)+" - ");}else{content.append("<a href='"+href+"'>"+titles.get(i)+"</a> - ");}}if(content.length()>0){this.pageContext.getOut().println(content.delete(content.length()-3, content.length()));}} catch (Exception e) {e.printStackTrace();throw new JspException(e);}return super.doStartTag();}private void parseParent(Element parent){Iterator<Element> it = parent.elementIterator();while(it.hasNext()){Element temp = it.next();Attribute attr = temp.attribute("path");if(attr!=null){if(attr.getText().equals(currentFilePath)){target = temp;return;}}parseParent(temp);}}}

 sitemap.tld文件（存放在WEB-INF\tlds下）：
Xml代码  
 

<?xml version="1.0" encoding="UTF-8" ?><taglib xmlns="http://java.sun.com/xml/ns/javaee"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"    version="2.1">    <description>站点导航标签</description><display-name>myTaglib siteMap</display-name><tlib-version>1.1</tlib-version>        <short-name>tagUtil</short-name>    <uri>http://tag.market.org/jsp/tagutil/sitemap</uri>    <tag><description>面包屑标签</description><name>siteMap</name><tag-class>com.market.common.SiteMapTag</tag-class><body-content>empty</body-content>    </tag>    </taglib>

 
 在项目的src下面添加sitemap.xml文件：
 
Xml代码 
<?xml version="1.0" encoding="UTF-8"?>  

<!-- 配置文件说明， sitemap根节点,title是页面上显示的内容，  
   href是超链接，path是该请求页面的物理路径 
--> 
<sitemap title="音乐社区" href="index.action">  
    <node  title="用户模块">  
        <node path="/WEB-INF/pages/user/register_view.jsp" href="user/registerView.action"  title="用户注册" />  
    </node> 
</sitemap>  
  
 
要使用的jsp页面加入标签指令：

<%@taglib uri="http://tag.forever.org/jsp/tagutil/sitemap" prefix="tagUtil" %> 

 

如果运行报找不到 tld文件就在web.xml的web-app节点下加入

<jsp-config>
  <taglib>
   <taglib-uri>/sitemap.tld</taglib-uri>
   <taglib-location>/WEB-INF/tlds/sitemap.tld</taglib-location>
  </taglib>
 </jsp-config>

那在jsp的标签指令需要改为  <%@taglib uri="/sitemap.tld" prefix="tagUtil" %>

 在想放的位置处加上标签：
 
您所在的位置：<tagUtil:siteMap/> 就可以出现面包屑导航了。