如何在JSP中呈现递归集合

忘是亡心i 2023-01-05 14:11 135阅读 0赞

# 一 使用tag文件 #

1.创建包含以下代码的JSP标记文件(WEB-INF / tags / folderGroups.tag)：

<%@ attribute name="list" required="true" %>
    <%@ taglib tagdir="/WEB-INF/tags" prefix="myTags" %>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <c:if test="${!empty list}">
        <ul>
        <c:forEach var="folderGroup" items="${list}">
            <li><c:out value="${folderGroup.name}"/></li>
            <myTags:folderGroups list="${folderGroup.subGroups}"/>
        </c:forEach>
        </ul>
    </c:if>

2.标签以递归方式调用自身以生成文件夹树.

在你的JSP里面,做

<%@ taglib tagdir="/WEB-INF/tags" prefix="myTags" %>
    ...
    <myTags:folderGroups list="${info.folderGroups}"/>

# 二 复用jsp #

1.显示树的jsp页面，tree.jsp

<%@ 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>

2.递归构造树的页面recursive.jsp

<%@ 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>