Hashtable的问题

显示全部楼层 · 2010-3-1 11:19:06

用户:

物品号: 物品名: 物品数量: 物品价格:
[I]"> [I]">

复制代码
items=c.getItem();这段代码去掉就能正常显示页面,有了就会出现如下的错误:java.lang.ClassCastException

at org.apache.jsp.cart$jsp._jspService(cart$jsp.java:216)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)

at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:202)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:382)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:474)

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.access$0(ApplicationFilterChain.java:197)

at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:176)

at java.security.AccessController.doPrivileged(Native Method)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:172)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:201)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:246)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:368)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:1012)

at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1107)

at java.lang.Thread.run(Thread.java:534)

千问 · 2010-3-1 11:19:06

c.getItem() 的返回值是 hashtable吗？转型错误，返回的没办法转成hashtable

千问 · 2010-3-1 11:19:06

是HASHTABLE的,问题解决了,是我后面的代码,写错了.
不过,我现在还有个问题,我上面的代码就是购物车的部分,我用了SESSION BEAN,但是奇怪了,我只能记录一次购买的,不能记录多次,请问是什么原因呢?