问题描述
我已经编写了一个具有表单的JSP，该表单包含一个下拉列表和一个texfield。使用充当DAO和DTO的bean从MysqL数据库中填充下拉列表。问题是下拉菜单不会显示数据库中的值，但是当我从表单中删除文本字段并仅保留下拉菜单时，它会正常显示。有人知道为什么吗？请让我知道该怎么办。表单的代码如下：
有效的JSP：
<%@ page import=\"java.util.*\" %>
<%@ taglib prefix=\"c\" uri=\"http://java.sun.com/jsp/jstl/core\" %>
<jsp:useBean id=\"camp\" scope=\"session\" class=\"p1.campusDao\"/>
<%--
Document : addCamp
Created on : May 20,2011,11:28:31 AM
Author : ken
--%>
<%@page contentType=\"text/html\" pageEncoding=\"UTF-8\"%>
<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"
\"http://www.w3.org/TR/html4/loose.dtd\">
<html>
<head>
<style type=\"text/css\">
body {
background-color:#AFC7C7;
padding: 0;
margin: 0;
}
div.wrapper {
margin-left: 10%;
margin-right: 10%;
background-color:#6D7B8D;
height: 607px;
padding-top:0px;
border: thin solid #000000;
}
div#image{
padding-top:1%;
padding-bottom:1%;
}
div#adminlogin{
width:35%;
height:40%;
background-color:#AFC7C7;
border-width:thin;
border-style:solid;
border-color:#000000;
margin: 0 auto;
text-align:left;
overflow: hidden;
padding: 5px;
}
hr {
height:1px;
color:#000000;
background-color:#000000;
width:99%;
margin-left: 0 ;
margin-right: auto ;
border-style:solid;
}
.inputtext {
width: 250px;
height: 30px;
Font-Family:Arial;
Font-Size:18px
}
</style>
<script language=\"javascript\" type=\"text/javascript\">
function clearText(field){
if (field.defaultValue == field.value) field.value = \'\';
else if (field.value == \'\') field.value = field.defaultValue;
}
</script>
</head>
<body>
<div class=\"wrapper\">
<div id=\"image\">
<p>
<img src=\"${pageContext.request.contextpath}/images/logo.gif\"
alt=\"banner\"
width=100%
height=\"100\"
/></p>
</div><!--end of image div-->
<div id=adminlogin >
<p style=\"text-align:center\">Adding Hostel</p>
<hr/>
<form id=\"cam\" method=\"POST\" action=\"${pageContext.request.contextpath}/getHos\">
<select name=\"campuses\" size=\"1\" id=\"camps\">
<c:forEach items=\"${camp.stateList}\" var=\"ca\">
<%--<option value=\"1\"><c:out value=\"${ca.campnm}\"/></option>--%>
<option>${ca.campnm}</option>
</c:forEach>
</select>
<br>
<input type=\"Submit\" name=\"cmdsub\" value=\"SUBMIT\">
</form>
<p STYLE=\"color : #E41B17;\">${message}</p>
<c:remove var=\"message\" scope=\"session\" />
</div><%--end of admin login div--%>
</div>
</body>
</html>
<%@taglib prefix=\"sql\" uri=\"http://java.sun.com/jsp/jstl/sql\"%>
<%@ page import=\"java.util.*\" %>
<jsp:useBean id=\"campu\" scope=\"session\" class=\"p1.campusDao\"/>
<%--
Document : addCamp
Created on : May 20,11:28:31 AM
Author : ken
--%>
<%@page contentType=\"text/html\" pageEncoding=\"UTF-8\"%>
<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"
\"http://www.w3.org/TR/html4/loose.dtd\">
<html>
<head>
<style type=\"text/css\">
body {
background-color:#AFC7C7;
padding: 0;
margin: 0;
}
div.wrapper {
margin-left: 10%;
margin-right: 10%;
background-color:#6D7B8D;
height: 607px;
padding-top:0px;
border: thin solid #000000;
}
div#image{
padding-top:1%;
padding-bottom:1%;
}
div#adminlogin{
width:35%;
height:40%;
background-color:#AFC7C7;
border-width:thin;
border-style:solid;
border-color:#000000;
margin: 0 auto;
text-align:left;
overflow: hidden;
padding: 5px;
}
hr {
height:1px;
color:#000000;
background-color:#000000;
width:99%;
margin-left: 0 ;
margin-right: auto ;
border-style:solid;
}
.inputtext {
width: 250px;
height: 30px;
Font-Family:Arial;
Font-Size:18px
}
</style>
<script language=\"javascript\" type=\"text/javascript\">
function clearText(field){
if (field.defaultValue == field.value) field.value = \'\';
else if (field.value == \'\') field.value = field.defaultValue;
}
</script>
</head>
<body>
<div class=\"wrapper\">
<div id=\"image\">
<p>
<img src=\"${pageContext.request.contextpath}/images/logo.gif\"
alt=\"banner\"
width=100%
height=\"100\"
/></p>
</div><!--end of image div-->
<div id=adminlogin >
<p style=\"text-align:center\">Adding Hostel</p>
<hr/>
<form method=POST id=\"hostel\" action=\"${pageContext.request.contextpath}/getHos\">
<p/>
<%--The textfield for hostel name--%>
<label>Hostel Name<input type=\"text\" id=\"hostel\" name=\"hosNm\" value=\"\"/></label><br/>
<br/>
<label>Campus Name <select name=\"campuses\" size=\"1\" id=\"hostel\">
<c:forEach items=\"${campu.stateList}\" var=\"cam\">
<%--<option value=\"1\"><c:out value=\"${cam.campnm}\"/></option>--%>
<option>${cam.campnm}</option>
</c:forEach>
</select></label>
<br/>
<br/>
<input type=\"submit\" value=\"Add\" style=\"font-size:14pt; margin-left: 158px; height: 30px;\"/>
</form>
<p STYLE=\"color : #E41B17;\">${message}</p>
<c:remove var=\"message\" scope=\"session\" />
</div><%--end of admin login div--%>
</div>
</body>
</html>
解决方法
在第二个JSP中（您确实有两个单独的JSP文件吗？）
<%@taglib prefix=\"sql\" uri=\"http://java.sun.com/jsp/jstl/sql\"%>
<%@ taglib prefix=\"c\" uri=\"http://java.sun.com/jsp/jstl/core\" %>
<%@ page import=\"java.util.*\" %>