1、错误描述
javax.servlet.JspTagException:Illegal use of <when>-style tag without <choose >as its direct parent
2、错误原因
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jstl/core_rt"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<table>
<tr>
<th>时间</th>
<th>地域</th>
<th>姓名</th>
<th>年龄</th>
<th>性别</th>
<th>QQ</th>
<th>地址</th>
<th>爱好</th>
<th>备注</th>
</tr>
<tr>
<c:forEach var="area" varStatus="areaStatus" items="{areaList}">
<c:when test="areaList == null || areaList.size()==0">
<td colspan="9"><center>无数据</center></td>
</c:when>
<c:otherwise>
<td>${area.statisDate}</td>
<td>${area.areaDesc}</td>
<td>${area.username}</td>
<td>${area.age}</td>
<td>${area.sex}</td>
<td>${area.qq}</td>
<td>${area.address}</td>
<td>${area.intester}</td>
<td>${area.shuoMing}</td>
</c:otherwise>
</c:forEach>
</tr>
</table>
</body>
</html>
3、解决办法
（1）将<c:when></c:when>换成<c:if>
（2）利用struts2中的s标签中的<s:if>
javax.servlet.JspTagException:Illegal use of <when>-style tag without <choose >as its di
原文：http://blog.csdn.net/you23hai45/article/details/44628163