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Good day!
I tried using JSTL in java but there's an error:
exception
javax.servlet.ServletException: java.lang.InstantiationException: class session.Item : java.lang.InstantiationException: session.Item
root cause
java.lang.InstantiationException: class session.Item : java.lang.InstantiationException: session.Item
My code is as follows:
<%@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>
<title>DISPLAY ITEM</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<jsp:useBean id="invenItem" class="session.Item" scope="request"/>
<c:choose>
<c:when test="${invenItem != null}">
<h1>Inventory Item Details: JSP Tester</h1>
Stock ID : <jsp:getProperty name="invenItem" property="stockID" /><br/>
Name : <jsp:getProperty name="invenItem" property="itemName" /><br/>
Unit Price: <jsp:getProperty name="invenItem" property="unitPrice" /><br/>
On Stock : <jsp:getProperty name="invenItem" property="onStock" />
<h1> Inventory Item Details Tester: EL Method </h1>
Stock ID : ${invenItem.stockID} <br/>
Name : ${invenItem.itemName}<br/>
Unit Price: ${invenItem.unitPrice}<br/>
On Stock : ${invenItem.onStock}
</c:when>
<c:otherwise>
<%@ include file ="DataForm.html" %><br>
Item not existing!<br>
<%@ include file ="ItemEntry.html" %>
</c:otherwise>
</c:choose>
</body>
</html>
I've read this JLPT already and followed all the instructions there. Please help. Thank you.
EDIT...
I resolved the error as suggested, but still the JSTL (if else logic) is not working. HELP PLEASE!!!!
it seems that you forgot to reference the jstl core taglib at the beginning:
If
invenItemalready exists as a request attribute, then you don't need to use<jsp:useBean>to retrieve it, you can just use it directly in your JSP, so just remove the<useBean>line completely.If
invenItemdoesn't already exist as a request attribute, then<jsp:useBean>will create one for you, but whatever you put in theclassattribute must be the fully-qualified name of a class with a public, default constructor, else you'll get the exception you saw.