jstl处理递归问题

文章转自：http://www.iteye.com/topic/1116588

需要两个jsp页面，一个是你要显示树的jsp页面tree.jsp，一个是递归构造树的页面recursive.jsp

显示树的jsp页面，tree.jsp

Html代码


<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<div style=" float:left; display:block; margin:10px; overflow:auto; width:200px; height:300px; border:solid 1px #CCC; line-height:21px; background:#FFF;">

<ul class="tree">

<%@include file="recursive.jsp"%>

</ul>

</div>

递归构造树的页面recursive.jsp

Html代码


<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<li>

<a href="main.html" target="navTab" rel="main">${menu.name}</a>

<c:if test="${not empty menu.children}">

<ul>

<c:forEach var="menu" items="${menu.children}">

<c:set var="menu" value="${menu}" scope="request"/>

<jsp:include page="recursive.jsp"/>

</c:forEach>

</ul>

</c:if>

</li>

菜单Model,简单的一个Bean,树状结构的数据模型

Java代码


public class MenuItem{

private String name;

private String url;

private List<MenuItem> children = new ArrayList<MenuItem>();

public MenuItem(String name,String url){

this.name = name;

this.url = url;

}

public void addChildMenu(MenuItem menu){

this.children.add(menu);

}

.......

}

构造模拟数据

Java代码


MenuItem menu31 = new MenuItem("三级菜单1", "url31");

MenuItem menu32 = new MenuItem("三级菜单2", "url32");

MenuItem menu33 = new MenuItem("三级菜单3", "url33");

MenuItem menu34 = new MenuItem("三级菜单4", "url34");

MenuItem menu35 = new MenuItem("三级菜单5", "url35");

MenuItem menu21 = new MenuItem("二级菜单1", "url21");

menu21.addChildMenu(menu31);

menu21.addChildMenu(menu32);

menu21.addChildMenu(menu33);

MenuItem menu22 = new MenuItem("二级菜单2", "url22");

menu22.addChildMenu(menu34);

menu22.addChildMenu(menu35);

MenuItem root = new MenuItem("根目录", "root");

root.addChildMenu(menu21);

root.addChildMenu(menu22);

以上就是通过jstl标签构造生成树的全部代码了

最后生成的html代码

Html代码


<div style=" float:left; display:block; margin:10px; overflow:auto; width:200px; height:300px; border:solid 1px #CCC; line-height:21px; background:#FFF;">

<ul class="tree">

<li>

<a href="main.html" target="navTab" rel="main">根目录</a>

<ul>

<li>

<a href="main.html" target="navTab" rel="main">二级菜单1</a>

<ul>

<li><a href="main.html" target="navTab" rel="main">三级菜单1</a></li>

<li><a href="main.html" target="navTab" rel="main">三级菜单2</a></li>

<li><a href="main.html" target="navTab" rel="main">三级菜单3</a></li>

</ul>

</li>

<li>

<a href="main.html" target="navTab" rel="main">二级菜单2</a>

<ul>

<li>

<a href="main.html" target="navTab" rel="main">三级菜单4</a>

<a href="main.html" target="navTab" rel="main">三级菜单5</a>

</li>

</ul>

</li>

</ul>

</li>

</ul>

</div>