JSP and beans

Is the bean spec for use w/ jsp any different than the one for J2EE? are there any required methods for use w/ jsp like in tag handlers?
Thanks

just make sure that you meet the basics of the bean properties for example
your bean class should meet the following constraints
no argument constructer
if you have instance variables i.e count
make sure that you have public getter and setters for it
getCount()
setCount(int c)
you may add as much methods as you want
make sure that your bean is existing either under web-inf/classes
or web-inf/lib
regards

Similar Messages

Please recommend IDE for JSP and Beans

Hi guys,
I am looking for a decent IDE to work with JSP and Beans. I have tried JBuilder which has too much going on at the same time and I find it to be an overkill for what I am doing; I find NetBeans kind of irritating. I develop web applications, hence I dont need any GUI stuff for beans.
Just looking for something that will enable me to rapidly develop beans as a support system for JSP pages and at the same time, it should provide good support for coding JSP pages. Little bit of management functions wont hurt either, but are not required. I dont mind if I have to pay for the IDE. Any recommendations?

I like Eclipse for Java Development, and I use the MyEclipse plug-in for J2EE development.
There is a free J2EE plug-in (Lomboz) but I'd much rather pay the $29.99/year for MyEclipse. It's been perfect for me.

Help on JSP and Beans!

Hi! I am new to JSP and I need help on how to utilize java bean on JSP. I have gone through this forum, I found similar question but did not find any answer that could solve my question. Tons of thanks to anyone who could help me out!
I have a java bean class called Bean1, which I put under /ROOT/WEB-INF/classes/, and a JSP file that utilizes class Bean1, saved under /ROOT/, which should be a correct way indicated by several posts I found in this forum. But when I try to compile the JSP file over TOMCAT4.1 over http://localhost:8080/beanexample1.jsp, it throws me a lot of error messages (see below). I've been struggling for so long. Any help is greatly apprecitated! Thanks!
Bo
The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 0 in the jsp file: /beanexample1.jsp
Generated servlet error:
[javac] Compiling 1 source file
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:41: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
Bean1 bean1 = null;
^
An error occurred at line: 0 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:43: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
bean1 = (Bean1) pageContext.getAttribute("bean1", PageContext.PAGE_SCOPE);
^
An error occurred at line: 0 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:46: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
bean1 = (Bean1) java.beans.Beans.instantiate(this.getClass().getClassLoader(), "Bean1");
^
An error occurred at line: 13 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:66: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageContext.findAttribute("bean1")).getName())));
^
An error occurred at line: 16 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:69: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageContext.findAttribute("bean1")).getSeventhPrimeNumber())));
^
An error occurred at line: 19 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:72: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageContext.findAttribute("bean1")).getCurrentTime())));
^
An error occurred at line: 27 in the jsp file: /beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\beanexample1_jsp.java:79: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageContext.findAttribute("bean1")).getColor())));
^
7 errors
     at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:130)
     at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:293)
     at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:340)
     at org.apache.jasper.compiler.Compiler.compile(Compiler.java:352)
     at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:474)
     at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:184)
     at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
     at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:260)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
     at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
     at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
     at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:432)
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:386)
     at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:534)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:530)
     at java.lang.Thread.run(Thread.java:484)

you need to put your bean in a package. do this by
making a sub directory under the classes directory,
let's say you call it "mybeans".
so copy Bean1.java to
/ROOT/WEB-INF/classes/Bean1.java
add the line "package mybeans;"
to the top of the Bean1.java file,
and then compile it there.
the standard way to use the bean in your jsp file is like this:
<jsp:useBean id="thisbean" scope="page" class="mybeans.Bean1" />
this <jsp:usebean> tag instantiates the bean for you.
then refer to it by its id:
thisbean.myMethod();
thisbean.setProperty();
I have a java bean class called Bean1, which I put
under /ROOT/WEB-INF/classes/, and a JSP file that
utilizes class Bean1, saved under /ROOT/, which should
be a correct way indicated by several posts I found in
this forum. But when I try to compile the JSP file
over TOMCAT4.1 over
http://localhost:8080/beanexample1.jsp, it throws me a
lot of error messages (see below). I've been
struggling for so long. Any help is greatly
apprecitated! Thanks!
Bo
The server encountered an internal error () that
prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile
class for JSP
An error occurred at line: 0 in the jsp file:
/beanexample1.jsp
Generated servlet error:
[javac] Compiling 1 source file
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:4
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
Bean1 bean1 = null;
^
An error occurred at line: 0 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:4
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
bean1 = (Bean1)
(Bean1) pageContext.getAttribute("bean1",
PageContext.PAGE_SCOPE);
^
An error occurred at line: 0 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:4
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
bean1 = (Bean1)
1 = (Bean1)
java.beans.Beans.instantiate(this.getClass().getClassLo
der(), "Bean1");
^
An error occurred at line: 13 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:6
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageCont
xt.findAttribute("bean1")).getName())));
^
An error occurred at line: 16 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:6
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageCont
xt.findAttribute("bean1")).getSeventhPrimeNumber())));
^
An error occurred at line: 19 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:7
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageCont
xt.findAttribute("bean1")).getCurrentTime())));
^
An error occurred at line: 27 in the jsp file:
/beanexample1.jsp
Generated servlet error:
C:\Program Files\Apache Group\Tomcat
4.1\work\Standalone\localhost\_\beanexample1_jsp.java:7
: cannot resolve symbol
symbol : class Bean1
location: class org.apache.jsp.beanexample1_jsp
out.print(JspRuntimeLibrary.toString((((Bean1)pageCont
xt.findAttribute("bean1")).getColor())));
^
7 errors
at
org.apache.jasper.compiler.DefaultErrorHandler.javacEr
or(DefaultErrorHandler.java:130)
at
org.apache.jasper.compiler.ErrorDispatcher.javacError(
rrorDispatcher.java:293)
at
org.apache.jasper.compiler.Compiler.generateClass(Comp
ler.java:340)
at
org.apache.jasper.compiler.Compiler.compile(Compiler.j
va:352)
at
org.apache.jasper.JspCompilationContext.compile(JspCom
ilationContext.java:474)
at
org.apache.jasper.servlet.JspServletWrapper.service(Js
ServletWrapper.java:184)
at
org.apache.jasper.servlet.JspServlet.serviceJspFile(Js
Servlet.java:295)
at
org.apache.jasper.servlet.JspServlet.service(JspServle
.java:241)
at
javax.servlet.http.HttpServlet.service(HttpServlet.jav
:853)
at
org.apache.catalina.core.ApplicationFilterChain.intern
lDoFilter(ApplicationFilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilt
r(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(S
andardWrapperValve.java:260)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(Stand
rdPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(Containe
Base.java:995)
at
org.apache.catalina.core.StandardContextValve.invoke(S
andardContextValve.java:191)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(Stand
rdPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(Containe
Base.java:995)
at
org.apache.catalina.core.StandardContext.invoke(Standa
dContext.java:2415)
at
org.apache.catalina.core.StandardHostValve.invoke(Stan
ardHostValve.java:180)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke
ErrorDispatcherValve.java:170)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.ErrorReportValve.invoke(Err
rReportValve.java:172)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:641)
at
org.apache.catalina.core.StandardPipeline.invoke(Stand
rdPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(Containe
Base.java:995)
at
org.apache.catalina.core.StandardEngineValve.invoke(St
ndardEngineValve.java:174)
at
org.apache.catalina.core.StandardPipeline$StandardPipe
ineValveContext.invokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(Stand
rdPipeline.java:480)
at
org.apache.catalina.core.ContainerBase.invoke(Containe
Base.java:995)
at
org.apache.coyote.tomcat4.CoyoteAdapter.service(Coyote
dapter.java:223)
at
org.apache.coyote.http11.Http11Processor.process(Http1
Processor.java:432)
at
org.apache.coyote.http11.Http11Protocol$Http11Connecti
nHandler.processConnection(Http11Protocol.java:386)
at
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolT
pEndpoint.java:534)
at
org.apache.tomcat.util.threads.ThreadPool$ControlRunna
le.run(ThreadPool.java:530)
     at java.lang.Thread.run(Thread.java:484)

JSP AND BEAN PROBLEm   java.lang.nullpointerexception   help me please

hello i have a problem, when i open login.jsp and enter the form i have nullpointerexception. i don't understand where i wrong... i use tomcat 5.5 ... sorry for my english i'm italian and i speak only italian :(
login.jsp this is the code of the java server page
<html>
<%@ page language="java" import="java.sql.*" %>
<jsp:useBean id="lavoro" scope="page" class="Ok.Dino"/>
<%@ page session="false" %>
<style type="text/css">

</style>
<body>
<%if(request.getMethod()=="GET"){
%>
<form action="login.jsp" method= "POST" name="frmlogin" id="frmlogin">
     <div align="center">
       <p class="style1">AUTENTICAZIONE</p>
       <p> </p>
       <table width="318" height="140" border="1">
        <tr>
          <td width="95" height="60" bordercolor="#000000" bgcolor="#0066CC"><p align="center"><strong>USER</strong></p>          </td>
          <td width="207" bgcolor="#0099CC"><p align="center">
            <input type="text" name="txtnome"></p>
          </td>
        </tr>
        <tr>
          <td height="72" bordercolor="#000000" bgcolor="#0066CC"><strong>PASSWORD</strong> </td>
          <td width="207" bgcolor="#0099CC"><div align="center">
            <input name="pwdtxt" type="password">
          </div></td>
        </tr>
      </table>
       <table width="318" border="1">
        <tr>
          <td width="318" height="87"> <div align="center">
            <input name="submit" type="submit" value="invia" >
          </div>
          <p align="center"><strong><span class="style4">Se non sei registrato fallo <a href="file:///C|/Documents and Settings/access/Documenti/My Received Files/registrazione.jsp">adesso </a></span></strong></p></td>
        </tr>
      </table>
       <p> </p>
       <p> </p>
</div>
</form>
<%}else { %>
<%lavoro.settxtnome(request.getParameter("txtnome"));%>
<%!ResultSet rs=null;
     String x=null;
%>
<% lavoro.cn_db("dbutenti");%>
<% rs=lavoro.run_query("SELECT user FROM utenti");%>
<%}%>
</body>
</html>and this is the bean code
package Ok;
import java.sql.*;
public class Dino
private String txtnome,pwdtxt;
private Connection cn=null;
private Statement st=null;
private ResultSet Rs=null;
public String gettxtnome()
return txtnome;
public String getpwdtxt()
return pwdtxt;
public void settxtnome(String n)
this.txtnome=n;
public void setpwdtxt(String n)
this.pwdtxt=n;
public void cn_db(String db)
          if(cn==null){
          //1. Caricamento del driver
          try{
               Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
          }catch(ClassNotFoundException cnfe){
               System.out.println("impossibile caricare il driver");
               System.exit(1);
          try{
               //2. Connessione al DB
               cn = DriverManager.getConnection("jdbc:odbc:"+db);
               //3. creazione degli oggetti Statement e ResultSet
               st =cn.createStatement();
          }catch(SQLException e){
               System.out.println(e+"jjj");
}else{
     System.out.print("errore database gi�� creato");
public ResultSet run_query(String qr)
     try{
Rs=st.executeQuery(qr);
     }catch(SQLException e)
     System.out.print(e+"ecco l'error");
     return Rs;
}

Do you understand when a NullPointerException will be thrown? This will be thrown if you want to access an uninstantiated Object.
So look to the stacktrace and go to the line where the NPE is been thrown and doublecheck if the object reference is actually instantiated.
Or add a null-check to the object reference:if (someObject != null) {
    someObject.doSomething();
}or just instantiate it:if (someObject == null) {
    someObject = new SomeObject();
someObject.doSomething();

Where do I place JSP and Beans?

Hello,
I have just installed JDeveloper and have no idea where to place JSP pages and Bean class files so thet JDeveloper can access them when I run or debug a page.
Any help would be appreciated.

In JDeveloper, applications are grouped by one or more projects and a workspace containing projects. In your case, if you already have beans and JSPs built, here's what you need to do:
1. Create a new workspace.
2. Create a project using the 'create a project from existing source code' option.
3. Optionally check the 'copy to project's source directory' to include your files in the project.
Hope this helps,
Lynn
Java Tools Team

Memory leak with jsp and beans

The application we have created has one particular page that is designed to stay up in the browser and refresh with new information from database queries once every 60 seconds. Running with Tomcat3.2.1 and IE5.5
The problem is that the memory usage of java.exe continues to grow until the machine crashes from out of memory. It does take more than 24 hours to crash.
Things I have tried to do to track down the problem or eliminate the problem.
- I have explicitly set the scope of the beans to "page"
- I have watched the DatabaseAccess.class (the beans are all extended from this class) and put in code to watch how many instantiations of the class are made and subsequently garbage collected. This appears to be where the memory leak may reside - hundreds of instantiations from some other source than the page I am displaying.
- the top frame makes database queries for security and display of a menu system dependant upon security clearance. It does not set any time for refresh (refresh == 0). Nor does it explicitly set a scope for the beans.
- I have run a different jsp engine to see if this was directly related to Tomcat - same problem with resin2.0.0
The main jsp page that is in the bottom section of the page has the following code:
** only the relevant lines are included here
<%@ include file="../../common.jsp" %>
<%
refresh=60;
%>
<head>
<%@ include file="../../meta_head.jsp" %>
</head>
<body bgcolor="#FFFFFF" text="#003399" link="#660099" vlink="#990099" alink="#006666" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<%@ include file="../../access.jsp" %>
<%@ include file="../../page_title.jsp" %>
<jsp:useBean id="Line" class="jsp.Line" scope="page" />
<jsp:useBean id="Machine" class="jsp.Machine" scope="page"/>
<jsp:useBean id="Alarm_log" class="jsp.Alarm_log" scope="page"/>
contents of meta_head.jsp
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<META HTTP-EQUIV= "expires" content = "0">
<META HTTP-EQUIV="Pragma" CONTENT="no_cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache" forua="true">
<META NAME="robots" content="NOINDEX,NOFOLLOW">
<%
if (refresh > 0)
%>
<meta http-equiv="Refresh" content="<%= refresh %>">
<%
If anyone has some suggestions on how to trap this memory leak, it would be terrific. Or, some other things to try to stop the instantiation of the DatabaseAccess object (perhaps setting the scope of the beans in the header to "session" or "application"?).
Thanks in advance.
Roberta

jsp:useBean tags scope declaration :
page = Create a new instance on each load.
session = Load instance from the session, if not there, create one
application = Load instance from the ServletContext, if not there, create one.
Not sure how you are populating the data variables, but make sure you are closing all ResultSet, (Prepared)Statement, and Connection objects.

Handling Session in jsp and bean scope

i have problems with handling session in jsp
I want to check on all jsp pages
first thing is session is null
i want to him to be redirected to first page
and he should not be able to go ahead
I tried
if(session ==null)
response.sendRedirect("Login.jsp");
but this does not seem to work
It is very crtical problem can any one answer
this asap
Also i wanted to know that
I have bean which in turn calls static methods of another class which holds all DomainTable(database tables which do not change frequently)
Information .
This is bean is being implemented by me
in seession scope in a jsp
Do u guys think it would be goo idea to change
scop of this bean as Application in jsp
if so what would be advantages for same
I would appericate if i could a quick reply on both
question
as i am time crunch
arsh

You will always get some value of session and your code wont work. At the end of your Login.jsp, you should create a sesssion and store attributes. Check for these attributes in session, rather than checking session==null.

Using Collections within JSP and beans

Hi I have a bean setup that contains a collection (linkedList of objects)
A servlet sets up all the information and forwards to a jsp page
ResourceInformation resourceInfo = new ResourceInformation();
         resourceInfo.setResourceList(list);
         request.setAttribute("resourceInformation",resourceInfo);
         RequestDispatcher dispatcher = request.getRequestDispatcher(address);
         dispatcher.forward(request,response);My question is what is the prefered way of iterating through this collection from the jsp page
as I havent been able to find any examples of JSP pages utilising collections
Thanks a lot

The JSTL (http://java.sun.com/products/jsp/jstl/) contains a <c:forEach> tag you can use to iterate collections - e.g:
<c:forEach var="resource" items="${requestScope.resourceInformation.resourceList}">
<tr>
    <td>${resource.name}</td>
</tr>
</c:forEach>

JSP and Bean

Hi!
I am trying to write a simple code using bean and JSP.
I have 3 pages:
GetName.html (This is a html form which calls SaveName.jsp)
<HTML>
<BODY>
<FORM METHOD=POST ACTION="SaveName.jsp">
What's your name? <INPUT TYPE=TEXT NAME=username SIZE=20><BR>
What's your e-mail address? <INPUT TYPE=TEXT NAME=email SIZE=20><BR>
What's your age? <INPUT TYPE=TEXT NAME=age SIZE=4>
<P><INPUT TYPE=SUBMIT>
</FORM>
</BODY>
</HTML>
SaveName.jsp (In this i am using a bean to store the field data)
<jsp:useBean id="user" class="UserData" scope="session">
</jsp:useBean>
<jsp:setProperty name="user" property="*"/>
<HTML>
<BODY>
Continue
</BODY>
</HTML>
UserData.java
public class UserData {
String username;
String email;
int age;
public UserData()
public void setUsername( String value )
username = value;
public void setEmail( String value )
email = value;
public void setAge( int value )
age = value;
public String getUsername() { return username; }
public String getEmail() { return email; }
public int getAge() { return age; }
I am using a WebLogic Server 6.1. I kept the UserData class file under the WEB_INF\Classes folder.
I am getting an error as "cannot resolve the symbol" in line 1 of SaveName.jsp
I would appreciate if you somebody could give a thought.
Awaiting reply.

Hi,
You have put the Bean UserData in the directory WEB_INF\classes but in your code you are not specifing to that directory. Here is the correct code.
jsp:useBean id="user" class="classes.UserData" scope="session">

Passing values between JSP and Bean

I am trying to validate a date entered by the user on a form. I need to do an "alert" when the user enters a date outside of the valid range depending on a value entered in a drop down.
Am doing this in checkform function. Here is what I want to do:
1. Send the the value from the drop down and the date to bean to do the calculations. Call the EJB function from checkform.
2. Get a string values back into the jsp from the bean
3. Blow an error to the user to enter a valid date.
Any help in this case would be greatly appreciated.
Thanks.

I only see some design requirements.
What's the exact coding question? Where are you stucking while coding those requirements accordingly?

JSP Accesing Bean Problem

I need a help in this jsp and bean Please provide the solution
          This is the bean
          import java.text.*;
          import java.util.*;
          import java.io.Serializable;
          public class DateBean implements Serializable {
          public DateBean() {}
          SimpleDateFormat sdf;
          public void setFormat(String format) {
          sdf = new SimpleDateFormat(format);
          public String getCurrentTime() {
          return sdf.format(new Date());
          This is the date.jsp
          <html>
          <head>
          <title>A JSP that sets a property</title>
          </head>
          <body>
          The current time and date, in several formats, courtesy
          a bean:<p>
          
          <jsp:useBean
          id="date"
          class="DateBean"/>
          <ul>
          <jsp:setProperty name="date" property="format"
          value="EEEE, MMMM dd yyyy 'at' hh:mm"/>
          <li><jsp:getProperty name="date" property="currentTime"/>
          <jsp:setProperty name="date" property="format"
          value="hh:mm:ss MM/dd/yy"/>
          <li><jsp:getProperty name="date" property="currentTime"/>
          <jsp:setProperty name="date" property="format"
          value="yyyyy.MMMMM.dd GGG hh:mm aaa"/>
          <li><jsp:getProperty name="date" property="currentTime"/>
          </ul>
          
          </body>
          </html>
          AND THIS is the compilation error
          Error: [jspc]: 1 file(s) failed:
          /dates.jsp
          [Compilation errors : ]
          E:\DateBean\__dates.java:134: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          DateBean date = null; //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:135: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = (DateBean)pageContext.getAttribute("date"); //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:138: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = (DateBean)pageContext.getAttribute("date"); //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:140: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = new DateBean(); //[ /dates.jsp; Line: 13]
          ^
          4 errors
               at weblogic.jspc.doCompile(Ljava.lang.String;Ljava.util.List;Lweblogic.utils.Getopt2;ZLjava.lang.String;)V(jspc.java:839)
               at weblogic.jspc.runJspc(Lweblogic.utils.classloaders.GenericClassLoader;Ljava.io.File;Ljava.util.Map;Z)V(jspc.java:632)
               at weblogic.jspc.runBodyInternal()V(jspc.java:410)
               at weblogic.jspc.runBody()V(jspc.java:319)
               at weblogic.utils.compiler.Tool.run([Ljava.lang.String;)V(Tool.java:146)
               at weblogic.utils.compiler.Tool.run()V(Tool.java:103)
               at weblogic.jspc.main([Ljava.lang.String;)V(jspc.java:708)
          java.lang.Exception: [Compilation errors : ]
          E:\DateBean\__dates.java:134: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          DateBean date = null; //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:135: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = (DateBean)pageContext.getAttribute("date"); //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:138: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = (DateBean)pageContext.getAttribute("date"); //[ /dates.jsp; Line: 13]
          ^
          E:\DateBean\__dates.java:140: cannot resolve symbol
          symbol : class DateBean
          location: class jsp_servlet.__dates
          date = new DateBean(); //[ /dates.jsp; Line: 13]
          ^
          4 errors
               at weblogic.jspc.doCompile(Ljava.lang.String;Ljava.util.List;Lweblogic.utils.Getopt2;ZLjava.lang.String;)V(jspc.java:842)
               at weblogic.jspc.runJspc(Lweblogic.utils.classloaders.GenericClassLoader;Ljava.io.File;Ljava.util.Map;Z)V(jspc.java:632)
               at weblogic.jspc.runBodyInternal()V(jspc.java:410)
               at weblogic.jspc.runBody()V(jspc.java:319)
               at weblogic.utils.compiler.Tool.run([Ljava.lang.String;)V(Tool.java:146)
               at weblogic.utils.compiler.Tool.run()V(Tool.java:103)
               at weblogic.jspc.main([Ljava.lang.String;)V(jspc.java:708)

I just wanted to say THANK YOU! This stuff can be a real pain when all the documentation shows everything should be working but it doesn't.
I will pass on this little piece of info to the next confused person.
shoot me an e-mail sometime [email protected]

How to upload a file into server using j2ee jsp and servlet with bean?

How to upload a file into server using j2ee jsp and servlet with bean? Please give me the reference or url about how to do that. If related to struts is more suitable.
Anyone help me please!

u don't need j2ee and struts to do file uploading. An example is as such
in JSP. u use the <input> file tag like
<input type="file"....>You need a bean to capture the file contents like
class FileUploadObj {
    private FormFile srcFile;
    private byte[] fileContent;
    // all the getter and setter methods
}Then in the servlet, you process the file for uploading
    * The following loads the uploaded binary data into a byte Array.
    FileUploadObj form = new FileUploadObj();
    byte[] byteArr = null;
    if (form.signFile != null) {
        int filesize = form.srcFile.getFileSize();
        byteArr = new byte[filesize];
        ByteArrayInputStream bytein = new ByteArrayInputStream (form.srcFile.getFileData());
        bytein.read(byteArr);
        bytein.close();
        form.setFileContent(byteArr);
    // Write file content using Writer class into the destination file in the server.
    ...

First use of jsp and java bean and "Unable to compile class for JSP" error

Hi,
I am trying to create my first jsp + java bean and I get a basic error (but I have no clue what it depends on exactly). Tomcat seems to cannot find my class file in the path. Maybe it is because I did not create a web.xml file. Did I forgot to put a line in my jsp file to import my bean?
Thank you very much for your help.
Here is my error:
An error occurred at line: 2 in the jsp file: /login.jsp
Generated servlet error:
[javac] Compiling 1 source file
/usr/local/tomcat/jakarta-tomcat-5/build/work/Catalina/localhost/test/org/apache/jsp/login_jsp.java:43: cannot resolve symbol
symbol : class CMBConnect
location: class org.apache.jsp.login_jsp
CMBConnect test = null;
I only have this in my directory:
test/login.jsp
test/WEB-INF/classes/CMBConnect.java
test/WEB-INF/classes/CMBConnect.class
Do I need to declare another directory in classes to put my class file in it and package my bean differently?
Here is my login.jsp:
<%@ page errorPage="error.jsp" %>
<jsp:useBean id="test" type="CMBConnect" scope="session" />
<html>
<head>
<title>my test</title>
</head>
<body>
<h3>Login information</h3>
<b><%=session.getValue("customerinfo.message")%></b>
<form> ....... </form>
</body>
</html>
and here is my CMBConnect.java:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class CMBConnect
public CMBConnect () { }
public String openConnection(String id, String password) {
String returnText = "";
try {
Connection con = null;
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
con = DriverManager.getConnection("jdbc:oracle:thin:@myserver.abc.com:1521:TEST", id, password);
if(con.isClosed())
returnText = "Cannot connect to Oracle server using TCP/IP...";
else
returnText = "Connection successful";
} catch (Exception e) { returnText = returnText + e; }
return returnText;
Thanks again!

Thanks for you help
I created the package and I get this error this time:
javax.servlet.ServletException: bean test not found within scope
     org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:822)
     org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:755)
     org.apache.jsp.login_jsp._jspService(login_jsp.java:68)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:268)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:277)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:223)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

JSP Compile Error when using dynamic ID in logic:iterate and bean:size

Hello,
I try to create a dynamic table with logic:iterate and bean:size tag. Dynamic means the attributes are written by scriptlet. Eg.:
<logic:iterate id="customerBean" name="<%= formName %>" property="<%= propertyName%>" length="<%= sRowSize%>">When I replace the id Attribute with propertyName I get compile errors, such as
the compiler doesn't know the value at runtime:
Unable to compile class for JSP An error occurred at line: 179 in the jsp file: /pages/formContent.jsp Generated servlet error: _newCustomer.java:1046: Missing term. java.lang.Object <%= propertyName %> = null; ^
Whats wrong ?
Thanks for your help

Solution: don't use a runtime expression for the id attribute.
The id attribute is used to declare
- an attribute in scope
- a scriptlet variable on the page
These are only available for the duration of the <logic:iterate> tag
The "id" is only used in your programming. You don't need to make it dynamic.

Problems with JSP and MySql bean.

Hi,
I'm new to JSP and I'm having some problems with it. I'm trying to do a simple login where a java class (bean?) handles the SQL injektion. I have deployed the page on tomcat and it works fine, except that the sqlinjektion does basically nothing. I have installed the mysql driver. I think there is something wrong with the java class, or the way im calling it. It does not produce any error. But its like it would never actually process the java code, because ive tried to append things to error string to see what is going on, nothing happens. everything stay null, no exceptions are thrown. If I implement the code to JSP itself, it does load the driver and print exception that there is no connection to database (which is correct). What am I missing? Code follows:
the sqlhandler:
public abstract class SqlInjektor {
     private static String Database = "*****";
     private static String serverName = "localhost:3306";
     private static String usrName="******";
     private static String passw="******";
     * @return Connection
     public static Connection createConnection(String error){
          Connection mySqlCon = null;
          try{
               Class.forName("com.mysql.jdbc.Driver").newInstance();
          catch(Exception E){
               PrintWriter out = response.getWriter();
               out.println("lol");
          String url = "jdbc:mysql://" + serverName + "/" + Database + "?user=" + usrName + "&password=" + passw;
          try{
               mySqlCon = DriverManager.getConnection(url);
          catch (Exception E){
               E.printStackTrace(System.out);
          return mySqlCon;
     * Metodi saa sy�tteen��n SQL komennon, jonka se suorittaa sek� palauttaa komennon tulokset.
     * @param command
     * @return ResultSet
     public static ResultSet querySQL(String command,String error, Connection con){
          ResultSet rs = null;
          try{
               Statement stmt = con.createStatement();
               rs = stmt.executeQuery(command);
          catch(Exception E){
               E.printStackTrace(System.out);
          return rs;
the jsp page:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page isErrorPage="false" %>
<%@ page import="java.sql.*" %>
<%@page import="ot3.User"%>
<%@page import="ot3.SqlInjektor"%>
<%@page import="Javax.servlet.jsp.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>vastaanotto</title>
</head>
<body>
<%!      String id;
     String password;
     String error = new String("Error!\n");
     User user;
%>
<%      user = new User();
     session.putValue("currentUser",user);
     id = request.getParameter("authName");
password = request.getParameter("Password");
     Connection conn=null;
     ResultSet rs=null;
     conn = SqlInjektor.createConnection(error);
     if(conn!=null){
          out.println("conn ok!");
          rs = SqlInjektor.querySQL("SELECT * FROM user WHERE id='" + id +"' AND password='" + password+"' COLLATE latin1_bin;",error,conn);}
     try {
          if (rs!= null && rs.next()){
               user.setID(rs.getInt("id"));
               user.setName(rs.getString("name"));
               user.setPassword(rs.getString("password"));
               user.setClearance(rs.getInt("clearance"));
               if(rs.getString("addedby")!=null)
                    user.setAdder(rs.getInt("addedby"));
               if(rs.getString("lastmodifier")!=null)
                    user.setModifier(rs.getInt("lastmodifier"));
               rs.close();%>
               ONNISTU!
          <%}
          else {
               out.println(error);
     } catch (SQLException e) {
          out.println(e.getMessage());
     }%>
</body>
</html>

Hi,
I'm new to JSP and I'm having some problems with it. I'm trying to do a simple login where a java class (bean?) handles the SQL injektion. I have deployed the page on tomcat and it works fine, except that the sqlinjektion does basically nothing. I have installed the mysql driver. I think there is something wrong with the java class, or the way im calling it. It does not produce any error. But its like it would never actually process the java code, because ive tried to append things to error string to see what is going on, nothing happens. everything stay null, no exceptions are thrown. If I implement the code to JSP itself, it does load the driver and print exception that there is no connection to database (which is correct). What am I missing? Code follows:
the sqlhandler:
public abstract class SqlInjektor {
     private static String Database = "*****";
     private static String serverName = "localhost:3306";
     private static String usrName="******";
     private static String passw="******";
     * @return Connection
     public static Connection createConnection(String error){
          Connection mySqlCon = null;
          try{
               Class.forName("com.mysql.jdbc.Driver").newInstance();
          catch(Exception E){
               PrintWriter out = response.getWriter();
               out.println("lol");
          String url = "jdbc:mysql://" + serverName + "/" + Database + "?user=" + usrName + "&password=" + passw;
          try{
               mySqlCon = DriverManager.getConnection(url);
          catch (Exception E){
               E.printStackTrace(System.out);
          return mySqlCon;
     * Metodi saa sy�tteen��n SQL komennon, jonka se suorittaa sek� palauttaa komennon tulokset.
     * @param command
     * @return ResultSet
     public static ResultSet querySQL(String command,String error, Connection con){
          ResultSet rs = null;
          try{
               Statement stmt = con.createStatement();
               rs = stmt.executeQuery(command);
          catch(Exception E){
               E.printStackTrace(System.out);
          return rs;
the jsp page:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page isErrorPage="false" %>
<%@ page import="java.sql.*" %>
<%@page import="ot3.User"%>
<%@page import="ot3.SqlInjektor"%>
<%@page import="Javax.servlet.jsp.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>vastaanotto</title>
</head>
<body>
<%!      String id;
     String password;
     String error = new String("Error!\n");
     User user;
%>
<%      user = new User();
     session.putValue("currentUser",user);
     id = request.getParameter("authName");
password = request.getParameter("Password");
     Connection conn=null;
     ResultSet rs=null;
     conn = SqlInjektor.createConnection(error);
     if(conn!=null){
          out.println("conn ok!");
          rs = SqlInjektor.querySQL("SELECT * FROM user WHERE id='" + id +"' AND password='" + password+"' COLLATE latin1_bin;",error,conn);}
     try {
          if (rs!= null && rs.next()){
               user.setID(rs.getInt("id"));
               user.setName(rs.getString("name"));
               user.setPassword(rs.getString("password"));
               user.setClearance(rs.getInt("clearance"));
               if(rs.getString("addedby")!=null)
                    user.setAdder(rs.getInt("addedby"));
               if(rs.getString("lastmodifier")!=null)
                    user.setModifier(rs.getInt("lastmodifier"));
               rs.close();%>
               ONNISTU!
          <%}
          else {
               out.println(error);
     } catch (SQLException e) {
          out.println(e.getMessage());
     }%>
</body>
</html>

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