java.lang.String cannot be cast to

[hdb5834661]

type Exception report

message

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

exception

org.apache.jasper.JasperException: Exception in JSP: /bookshowcart.jsp:58

55: <%for(Iterator iter=cart.getItems().iterator();iter.hasNext();)
56: {
57: ShoppingCartItem item=(ShoppingCartItem)iter.next();
58: BookDetails book=(BookDetails)item.getItem();
59: %>
60: <tr>
61: <td align="left" bgcolor="#ffffff">


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
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

java.lang.ClassCastException: java.lang.String cannot be cast to shop.BookDetails
org.apache.jsp.bookshowcart_jsp._jspService(org.apache.jsp.bookshowcart_jsp:159)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
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)

这句真的有错吗？
BookDetails book=(BookDetails)item.getItem();

[polarman]

item.getItem()取道的对象是String类型
当然不能强制成BoolDetails

[likgui]

关注

[hdb5834661]

我在类中方法定义
public Object getItem()
{
return item;
}
可以强制转换BoolDetails？

我前面也用到这种转换都可以运行
现在这里就出问题，实在不知道怎么回事～

[gloomyfish]

please check your setItem() method , it's trick !!!!

[hdb5834661]

自己顶一下～不想沉下去

[hdb5834661]

public ShoppingCartItem(Object anItem)
{
// TODO 自动生成构造函数存根
item=anItem;
quantity=1;
}
我不用setItem()