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WEB访问EJB3.0 有状态bean 的有关问题

热度:7276   发布时间:2013-02-26 00:00:00.0
WEB访问EJB3.0 有状态bean 的问题
写了一个有状态的会话bean 在main函数中访问没有问题,当我放到JSP中访问就出现问题了
下面是我的相关代码

远程接口

Java code
import javax.ejb.Remote;@Remotepublic interface CountNumber {    public int getnum();}




有状态Bean实现类

Java code
import javax.ejb.Stateful;import com.thr.stateful.CountNumber;public @Stateful class CountNumberBean implements CountNumber {    private int k=1;    public int getnum() {        k++;        return k ;    }}




如果在main函数中这样直接访问
Java code
        Context cx=new InitialContext();        CountNumber cn=(CountNumber)cx.lookup("CountNumberBean/remote");        System.out.println(cn.getnum());        Thread.sleep(2000);        CountNumber cn2=(CountNumber)cx.lookup("CountNumberBean/remote");        System.out.println(cn2.getnum());



就可以获得两个值,都是 2

但我想要在WEB应用中访问,就出错,这里是我的JSP页面
Java code
<%@ page language="java"  pageEncoding="ISO-8859-1"%><%@page import="com.thr.stateful.CountNumber"%><%@page import="javax.naming.Context"%><%@page import="javax.naming.InitialContext"%><html>  <head>    <title>My JSP</title>  </head>  <body>    <%        Context cx=new InitialContext();        CountNumber cn=(CountNumber)session.getAttribute("cn");        if(cn==null){            cn=(CountNumber)cx.lookup("CountNumberBean/remote");            session.setAttribute("cn",cn);        }      out.print(cn.getnum());     %>  </body></html>


下面是错误信息
控制台输出的错误信息

Java code
11:18:48,453 ERROR [[jsp]] Servlet.service() for servlet jsp threw exception java.lang.ClassCastException: $Proxy222 at org.apache.jsp.welcome_jsp._jspService(welcome_jsp.java:73) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:336) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446) at java.lang.Thread.run(Thread.java:595)
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