为何在后台action中传值到前台，得到的值为null（Structs开发的）
日期：2014-05-18 浏览次数：20682 次
为什么在后台action中传值到前台，得到的值为null（Structs开发的）
Action类：
public class DynaStyleAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
// TODO Auto-generated method stub
List weekWeather = DataSources.getWeekForecast();
request.setAttribute( "weekWeather ",weekWeather);
return mapping.findForward( "display ");
}
}
JSP页面
<%@ page contentType= "text/html;charset=UTF-8 " language= "java " %>
<%@ taglib uri= "http://java.sun.com/jsp/jstl/core " prefix= "c " %>
<html>
<head>
<title> Dynamic Style </title>
<style>
/* Even row */
.row1 {background-color:orange;}
/* Odd row */
.row0 {background-color:yellow;}
/* Title row */
.title {background-color:blue;color:white;text-align:center;}
</style>
</head>
<body>
<%
out.print(request.getAttribute( "weekWeather "));
%>
<div align= "center ">
<h3> Dynamic Style </h3>
<table width= "300 ">
<tr class= "title ">
<th width= "100 "> Day </th>
<th> Rain Percent </th>
</tr>
<c:forEach var= "day " items= "${weekWeather} " varStatus= "loop ">
<tr class= "row${loop.count%2} ">
<td align= "left "> ${day.item} </td>
<td align= "right "> ${day.percent}% </td>
</tr>
</c:forEach>
</table>
</div>
</body>
</html>
求高手帮忙！
------解决方案--------------------
List weekWeather = DataSources.getWeekForecast();
这个是不是能够的到呢？你自己试试这里是不是出问题了
------解决方案--------------------
那就证明List weekWeather = DataSources.getWeekForecast();的list就没有得到值，测试一下 if(weekWeather==null)
{
System.out.println( "null ");
}
else
{
System.out.println( "ok ");
}
如果是ok那就看你的getWeekForecast()方法把有问题
Action类：
public class DynaStyleAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
// TODO Auto-generated method stub
List weekWeather = DataSources.getWeekForecast();
request.setAttribute( "weekWeather ",weekWeather);
return mapping.findForward( "display ");
}
}
JSP页面
<%@ page contentType= "text/html;charset=UTF-8 " language= "java " %>
<%@ taglib uri= "http://java.sun.com/jsp/jstl/core " prefix= "c " %>
<html>
<head>
<title> Dynamic Style </title>
<style>
/* Even row */
.row1 {background-color:orange;}
/* Odd row */
.row0 {background-color:yellow;}
/* Title row */
.title {background-color:blue;color:white;text-align:center;}
</style>
</head>
<body>
<%
out.print(request.getAttribute( "weekWeather "));
%>
<div align= "center ">
<h3> Dynamic Style </h3>
<table width= "300 ">
<tr class= "title ">
<th width= "100 "> Day </th>
<th> Rain Percent </th>
</tr>
<c:forEach var= "day " items= "${weekWeather} " varStatus= "loop ">
<tr class= "row${loop.count%2} ">
<td align= "left "> ${day.item} </td>
<td align= "right "> ${day.percent}% </td>
</tr>
</c:forEach>
</table>
</div>
</body>
</html>
求高手帮忙！
------解决方案--------------------
List weekWeather = DataSources.getWeekForecast();
这个是不是能够的到呢？你自己试试这里是不是出问题了
------解决方案--------------------
那就证明List weekWeather = DataSources.getWeekForecast();的list就没有得到值，测试一下 if(weekWeather==null)
{
System.out.println( "null ");
}
else
{
System.out.println( "ok ");
}
如果是ok那就看你的getWeekForecast()方法把有问题
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