Problem with classes

hannahd · August 16th, 2006, 10:29 AM

Hello,

I am new to JavaServer pages, and I am having trouble getting both servlets and jsp to work on Tomcat 5.5

I can get jsp pages to run ok, but whenever I use the <jsp:usebean tag with a class of my own, I get the following error:

org.apache.jasper.JasperException: /hannah/test.jsp(2,0) The value for the useBean class attribute beans.Team is invalid.
    org.apache.jasper.servlet.JspServletWrapper.handle JspException(JspServletWrapper.java:510)
    org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:375)
    org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet .java:802)

root cause

org.apache.jasper.JasperException: /hannah/test.jsp(2,0) The value for the useBean class attribute beans.Team is invalid.
    org.apache.jasper.compiler.DefaultErrorHandler.jsp Error(DefaultErrorHandler.java:39)
    org.apache.jasper.compiler.ErrorDispatcher.dispatc h(ErrorDispatcher.java:405)
    org.apache.jasper.compiler.ErrorDispatcher.jspErro r(ErrorDispatcher.java:146)
    org.apache.jasper.compiler.Generator$GenerateVisit or.visit(Generator.java:1174)
    org.apache.jasper.compiler.Node$UseBean.accept(Nod e.java:1116)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.j ava:2163)
    org.apache.jasper.compiler.Node$Visitor.visitBody( Node.java:2213)
    org.apache.jasper.compiler.Node$Visitor.visit(Node .java:2219)
    org.apache.jasper.compiler.Node$Root.accept(Node.j ava:456)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.j ava:2163)
    org.apache.jasper.compiler.Generator.generate(Gene rator.java:3305)
    org.apache.jasper.compiler.Compiler.generateJava(C ompiler.java:198)
    org.apache.jasper.compiler.Compiler.compile(Compil er.java:295)
    org.apache.jasper.compiler.Compiler.compile(Compil er.java:276)
    org.apache.jasper.compiler.Compiler.compile(Compil er.java:264)
    org.apache.jasper.JspCompilationContext.compile(Js pCompilationContext.java:563)
    org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:303)
    org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet .java:802)

I have tried everything I can think of to fix it. I packaged the file correctly.

My CLASSPATH environment variable reads like this:

C:\Program Files\Apache Software Foundation\Tomcat 5.5\common\lib\servlet-api.jar;C:\Program Files\Apache Software Foundation\Tomcat 5.5\common\lib\jsp-api.jar;C:\Javafiles\beans;.

JAVA_HOME:

C:\Java\jdk1.5.0_08

PATH:

C:\Java\jdk1.5.0_08\bin

CATALINA_HOME is this:

C:\Program Files\Apache Software Foundation\Tomcat 5.5

The code for my bean reads like this:

package beans;

public class Team {

String name, manager;

public void setName(String name) {

this.name = name;

}

public String getName() {

return name;

}

public void SetManager(String manager) {
this.manager = manager;
}

public String getManager() {
return manager;

}

}

And here is my jsp code

<jsp:useBean id="t" scope="session" class="beans.Team"/>
<jsp:getProperty name="t" property="name"/>
<jsp:getProperty name="t" property="manager"/>

<html>
<body>
<FORM>
<INPUT TYPE="text" NAME="name">
<INPUT TYPE="text" NAME="manager">

</FORM>

</body>
</html>

I think it may be to do with the class not being found, but I have added it to the classpath.

What am I doing wrong?

Thanks

Hannah

panacea · August 16th, 2006, 05:51 PM

The message "The value for the useBean class attribute ..." means that a no-argument constructor is not available. One would think that since you don't have a constructor defined, a no-arg constructor would exist by default. But maybe you've simplified the example you gave, or perhaps you really do need to define the no-arg constructor. Give it a try! :)

Jon Emerson
http://www.jonemerson.net/

hannahd · August 17th, 2006, 04:58 AM

Hi,

Thanks for your reply. I assumed that because there were no other constructors, it would implicitly use a default one, but even so I did try that before, but still got the same error.

Hannah