求大虾帮忙！javabean的使用问题，小弟再次先谢过了

本文介绍了一个关于JSP页面使用JavaBean时出现的错误案例。错误主要源于重复定义了bean名称，导致服务器无法正常运行请求。文章通过具体代码示例展示了如何使用JavaBean，并分析了错误产生的原因。

test_bean.jsp 如下：

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" pageEncoding="gb2312"%>

<% request.setCharacterEncoding("gb2312"); %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>第一个javabean(成功!)</title>
<style type="text/css">

</style>
</head>

<body>

<jsp:useBean id="bean_id2" class="Jbean.Jbean_Exp" scope="page" >
<jsp:setProperty name="bean_id2" property="str_jbean" value="我爱你<jsp:useBean>And</jsp:useBean>" />
</jsp:useBean>

<jsp:getProperty name="bean_id2" property="str_jbean" />

</body>
</html>
javabean如下:

// Jbean_Exp.java
package Jbean ;

public class Jbean_Exp //java bean 的class 必须为public
{
String str_jbean="" ; //str 可以不为private型的

public Jbean_Exp() {}

public void setStr(String strs)
  {
   this.str_jbean=strs ;
  }
public String getStr()
  {
   return this.str_jbean ;
  }
}

报错如下：

type Exception report

message

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

exception

org.apache.jasper.JasperException: /MyJspWebs/SimpleJSPtext/Successed/test_bean.jsp(37,0) useBean: Duplicate bean name: {0}
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
	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

org.apache.jasper.JasperException: /MyJspWebs/SimpleJSPtext/Successed/test_bean.jsp(37,0) useBean: Duplicate bean name: {0}
	org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
	org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:405)
	org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:100)
	org.apache.jasper.compiler.Validator$ValidateVisitor.visit(Validator.java:516)
	org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
	org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
	org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
	org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
	org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
	org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
	org.apache.jasper.compiler.Validator.validate(Validator.java:1489)
	org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:166)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:295)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
	org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:305)
	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/5.5.20 logs.