日期:2014-05-18  浏览次数:20738 次

请教JSP中一个变量的含义
请教JSP中一个变量的含义

JSP文件中,
<input   type=text   maxlength= "20 "   size= "20 "   name   = "number "  
value= " <c:if   test= "${outstockone!=null} ">
<c:out   value= "${outstockone.number} "/>
</c:if> "/>

请问:
test= "${outstockone!=null} "中的outstockone代表什么参数?
好像根JSP的文件名没关系。要单判断它是不是空,凭啥呀?都不知道它的来历和含义。迷糊了

相关原文件:
===========   outstockone.jsp   ==============
<%@   taglib   prefix= "spring "   uri= "/spring "   %>
<%@   taglib   prefix= "c "   uri= "http://java.sun.com/jstl/core "   %>
<%@   taglib   prefix= "fmt "   uri= "http://java.sun.com/jstl/fmt "   %>
<%@   taglib   prefix= "tiles "   uri= "http://jakarta.apache.org/struts/tags-tiles "   %>

<html>
<head>
<%@   page  
language= "java "
contentType= "text/html;   charset=GB18030 "
pageEncoding= "GB18030 "
%>              
<meta   http-equiv= "Content-Type "   content= "text/html;   charset=GB18030 ">      
<title> OutStock   Step   One </title>
<LINK   href= "../theme/style.css "   rel= "stylesheet "   type= "text/css ">
</head>
<br>

<body>
<center>
<form   method= "POST "   action= "outstockbefore.htm ">
    <h1> OutStock   Step   One </h1>
    <hr>

    <table>
          <tr>
          <td> OutStock   Number: </td>
          <td>

<input   type=text   maxlength= "20 "   size= "20 "   name   = "number "   value= " <c:if   test= "${outstockone!=null} "> <c:out   value= "${outstockone.number} "/> </c:if> "/>
</td>
      </tr>
          <tr>
          <td> OutStock   Type: </td>
<td>
      <select   name= "type ">
      <OPTION   value= "11 "
      <c:if   test= "${outstockone!=null&&outstockone.type== '11 '} "> selected </c:if>
      > 材料出库 </OPTION>
      <OPTION   value= "12 "   <c:if   test= "${outstockone!=null&&outstockone.type== '12 '} "> selected </c:if>
      > 销售出库 </OPTION>
      </select>
          </td>
      </tr>
          <tr>
          <td> OutStock   Date: </td>
          <td> <input   type=text   maxlength= "20 " &nbs