servlet报错严重: Servlet.service() for servlet jsp threw exception java.lang.ClassCa

[Jstions]

严重: Servlet.service() for servlet jsp threw exception
java.lang.ClassCastException: com.yn.enrity.ShangPin cannot be cast to java.util.List
at org.apache.jsp.image02.ddinfo_jsp._jspService(ddinfo_jsp.java:349)
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:393)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
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.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:654)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:445)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:379)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:292)
at com.yn.cotroller.OrderServlet.xqOrder(OrderServlet.java:64)
at com.yn.cotroller.OrderServlet.doGet(OrderServlet.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
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.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
代码如下：
package com.yn.cotroller;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.yn.dao.OrderDao;
import com.yn.dao.ShangpinDao;
import com.yn.enrity.Order;
import com.yn.enrity.RegistUser;
import com.yn.enrity.ShangPin;

public class OrderServlet extends HttpServlet {
OrderDao dao = new OrderDao();

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

request.setCharacterEncoding("utf-8");
// 获取flag标志
String flag = request.getParameter("flag");
// 根据flag的值判断执行什么方法
if("all".equals(flag)){
showOrderAll(request,response);
}else if ("add".equals(flag)) {
this.addOrder(request, response);
}else if ("xq".equals(flag)) {
this.xqOrder(request, response);
}else if ("select".equals(flag)) {
this.selectOrder(request, response);
}else if ("update".equals(flag)) {
this.updateOrder(request, response);
}
}
/**
* 详情
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
private void xqOrder(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException{
int orderID = Integer.parseInt(request.getParameter("id"));
System.out.println(orderID);
List<Order> list = new ArrayList<Order>();
list = dao.queryOrderById(orderID);
request.setAttribute("list", list);

int spID = Integer.parseInt(request.getParameter("id"));
System.out.println(spID);
ShangPin list1 = new ShangPin();
ShangpinDao dao = new ShangpinDao();
list1 = dao.querySpByID(spID);
request.setAttribute("list1", list1);

// 跳转
request.getRequestDispatcher("image02/ddinfo.jsp").forward(request,
response);

}
/**
* 修改注册用户信息
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
private void updateOrder(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
//获取信息
int orderID = Integer.parseInt(request.getParameter("orderID"));
String ordername = request.getParameter("ordername");
String address = request.getParameter("address");
String zipcode = request.getParameter("zipcode");
String phone = request.getParameter("phone");

//修改信息
dao.updateOrder(new Order(orderID,ordername,address,zipcode,phone));
//回到列表
this.showOrderAll(request, response);

}
/**
* 添加注册用户
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
private void addOrder(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
//获取信息
// int registID = Integer.parseInt(request.getParameter("registID"));
// String username = request.getParameter("username");
// String pwd = request.getParameter("pwd");
// String gender = request.getParameter("gender");
// String email = request.getParameter("email");
// String phone = request.getParameter("phone");
// dao.AddUser(new RegistUser(registID,username,pwd,gender,email,phone));
// this.showRegistAll(request, response);

}
/**
* 显示全部注册用户信息
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
private void showOrderAll(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
List<Order> list = dao.queryOrderAll();
request.setAttribute("list", list);
request.getRequestDispatcher("image02/dingdan.jsp").forward(request,
response);

}
/**
* 根据ID查询
*
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
private void selectOrder(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
int id = Integer.parseInt(request.getParameter("id"));
List<Order> list1 = new ArrayList<Order>();
list1 = dao.queryOrderById(id);
request.setAttribute("list1", list1);

// 跳转
request.getRequestDispatcher("image02/dingdanupdate.jsp").forward(request,
response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

this.doGet(request, response);
}

}

[Jstions]

com.yn.enrity; public class ShangPin { private int spID; private String picture; private String spname; private String price; private int sptypeID; public ShangPin(){} public ShangPin(int spID, String picture, String spname, String price, int sptypeID) { super(); this.spID = spID; this.picture = picture; this.spname = spname; this.price = price; this.sptypeID = sptypeID; } public int getSpID() { return spID; } public void setSpID(int spID) { this.spID = spID; } public int getSptypeID() { return sptypeID; } public void setSptypeID(int sptypeID) { this.sptypeID = sptypeID; } public String getPicture() { return picture; } public void setPicture(String picture) { this.picture = picture; } public String getSpname() { return spname; } public void setSpname(String spname) { this.spname = spname; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } }

[dracularking]

类型转换错误，应该容易找到

[zhouxingchi9527]

List<Order> list = new ArrayList<Order>(); list = dao.queryOrderById(orderID); 这个 dao.queryOrderById(orderID)返回类型不是List吧