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Problem using Java Beans

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posted 18 years ago

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Hi I'm getting this error...

<%@ page import="java.sql.*" %>
<%@ page import="java.util.*" %>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 
 
<HTML>
<HEAD>
 
<TITLE>Show Employee Test with JSP</TITLE>
 
</HEAD>
 
<BODY bgcolor="#FFFFFF" font="#000000">
 
 
<%
 Statement statement;
 Connection con;
 ResultSet rs;
 
 Class.forName("com.mysql.jdbc.Driver");
 
 String url="jdbc:mysql://localhost:3306/empdb";
 String username="root";
 String passwd="open";
 
 Vector employeeList = new Vector();
 
 con = DriverManager.getConnection(url, username, passwd);
 out.println("Database connection succeded" + " ");
 
 String query="SELECT * FROM employee_tbl ORDER BY emp_id ASC";
 
 statement = con.createStatement();
 rs = statement.executeQuery(query);
 
 while (rs.next())
 {
%>
 
<jsp:useBean id="eb" class="employee.EmployeeBean" />
<jsp:setProperty name="empFName" property="fName" value="ASD" /> 
 
 
<%
 //employeeList.add(eb);
 out.println(rs.getString(2) + " ");
 }
 
 out.println("Query succeeded" + " ");
 
%>
 
</BODY>
 
</HTML>

Bean File

I can't seem to figure it out... Help please... Thanks...

[ October 18, 2005: Message edited by: Timothy Sam ]
[ October 18, 2005: Message edited by: Bear Bibeault ]

SCJP 1.5

Ben Souther

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posted 18 years ago

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What error?

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf

Krishna Srinivasan

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posted 18 years ago

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You must import the bean to Jsp file before using int on jsp :
employee.EmployeeBean

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Timothy Sam

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posted 18 years ago

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Sorry... Here's the error report...

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:359)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:306)
org.apache.jsp.employee.showemployee_jsp._jspService(org.apache.jsp.employee.showemployee_jsp:96)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.NullPointerException
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:320)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:306)
org.apache.jsp.employee.showemployee_jsp._jspService(org.apache.jsp.employee.showemployee_jsp:96)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.12 logs.

SCJP 1.5

Timothy Sam

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posted 18 years ago

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You must import the bean to Jsp file before using int on jsp

Hi, do you mean this like:

<%@ page import="java.sql.*" %>

Thanks...

SCJP 1.5

Ben Souther

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posted 18 years ago

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You don't need to import it.
The useBean tag will handle that for you.

You're giving the bean an id of "eb".
In your setProperty tag, you need to refer to it with that name.

<jsp:setProperty name="eb" property="fName" value......

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf

Timothy Sam

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posted 18 years ago

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Thanks for your reply Ben that was very helpful. However a new problem arised... I hope you won't mind me asking...

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Cannot find any information on property 'fName' in a bean of type 'employee.EmployeeBean'
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:363)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:306)
org.apache.jsp.employee.showemployee_jsp._jspService(org.apache.jsp.employee.showemployee_jsp:96)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.12 logs.

Here's my code...

showemployee.jsp

<%@ page import="java.sql.*" %>
<%@ page import="java.util.*" %>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<HTML>
<HEAD>
 
<TITLE>Show Employee Test with JSP</TITLE>
 
</HEAD>
 
<BODY bgcolor="#FFFFFF" font="#000000">

<%
 Statement statement;
 Connection con;
 ResultSet rs;
 
 Class.forName("com.mysql.jdbc.Driver");
 
 String url="jdbc:mysql://localhost:3306/empdb";
 String username="root";
 String passwd="open";
 
 Vector employeeList = new Vector();
 
 con = DriverManager.getConnection(url, username, passwd);
 out.println("Database connection succeded" + " ");
 
 String query="SELECT * FROM employee_tbl ORDER BY emp_id ASC";
 
 statement = con.createStatement();
 rs = statement.executeQuery(query);
 
 while (rs.next())
 {
%>
 
<jsp:useBean class="employee.EmployeeBean" id="eb"/>
[B]<jsp:setProperty name="eb" property="fName" value="ASD" /> [/B]

<%
 //employeeList.add(eb);
 out.println(rs.getString(2) + " ");
 }
 
 out.println("Query succeeded" + " ");
 
%>
 
</BODY>
 
</HTML>

and my bean file...

EmployeeBean.java

SCJP 1.5

Ben Souther

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posted 18 years ago

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I wonder if Jasper got thrown off by the two upper case letters just after the "get" portion of the property.

Try property="fname".
[ October 19, 2005: Message edited by: Ben Souther ]

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf

Timothy Sam

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posted 18 years ago

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Tried changing property="fName" to property="fname"... Still won'y work... Thanks for the quick response...

SCJP 1.5

Ben Souther

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posted 18 years ago

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I just tried with FName and it worked.

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf

Timothy Sam

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posted 18 years ago

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FINALLY WORKED! Thanks a lot! What could be the reason fName didn't work? It's clearly defined in my javabean...

SCJP 1.5

Ben Souther

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posted 18 years ago

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I'm guessing that it's trying to prevent things like:
property="sSN" for properties that are acronyms like getSSN().

I haven't seen the exact syntax rules in the JSP spec in a long time.
The link is in my signature if you want to look for them.

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf

Timothy Sam

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posted 18 years ago

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Thank you for you reply! that was very very very helpful!

SCJP 1.5