cannot be cast to java.util.Collection

package com.hollycrm.hollyv8.zsptest.zsp.service.impl;import ...
public class UserManagerServiceImpl implements UserManagerService {
    private UserManagerDao userDao;

    public void setUserManagerDao(UserManagerDao userDao){

       this.userDao = userDao ;
     }
     public UserManagerDao getUserManagerDao(){

       return this.userDao ;
     }
     public void addUser(UserInfo user) {       this.userDao.add(user) ;     }     public void deleteUser(String account) {
     // TODO Auto-generated method stub
     this.userDao.delete(account) ;
     }
     public UserInfo getUser(String account) {
     // TODO Auto-generated method stub
     return this.userDao.getUserInfo(account);
     }
     public UserInfo getUser(String name, String account) {
     // TODO Auto-generated method stub
     List<UserInfo> list = this.userDao.getUserInfo(name, account);
     if(list != null&&list.size() > 0){
     return list.get(0);
     }else{
     return null;
     }
     }
     public List<UserInfo> listUser() {
     // TODO Auto-generated method stub
     return this.userDao.getUserInfos();
     }
     public void saveOrUpdate(UserInfo user) {
     // TODO Auto-generated method stub
     this.userDao.saveOrUpdate(user);
     }
     public UserInfo query(){
     return this.userDao.query();
     } }
com.hollycrm.hollyv8.zsptest.zsp.service.impl.UserManagerServiceImpl cannot be cast to java.util.Collection
大家帮我看看这是怎么回事？

解决方案 »

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你什么情况下报这个错？
倒是发现你的注入怪怪的。public void setUserManagerDao(UserManagerDao userDao){

          this.userDao = userDao ;
         }
         public UserManagerDao getUserManagerDao(){

          return this.userDao ;
         }
应该是想用setter注入吧，但是你的方法名为什么不是setUserDao,却是setUserManagerDao，你这样如何注入？
方法名一定要用setUserDao吗？
我是在打开jsp页面的时候报这个错误的。
你用setter注入， private UserManagerDao userDao;必须是setUserDao。你jsp中如何写的，贴一下。
这是主页面，zsp_search.jsp
<%@ page language="java" import="java.util.*,com.hollycrm.hollyv8.constant.*"  pageEncoding="GBK"%>
<%@ taglib prefix="view" uri="/WEB-INF/hollycrm-view.tld"  %>
<%@ taglib prefix="sv" uri="/WEB-INF/hollycrm-services.tld"  %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<%@ page import="java.util.ArrayList"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html>
<head><title>人员查询系统</title>
<link rel="stylesheet" type="text/css" href="<%=request.getContextPath() %>/framework/css/style.css">
<link rel="stylesheet" type="text/css" href="<%=request.getContextPath() %>/framework/css/hollycrm.css">

<script language="javascript" src="<%=request.getContextPath() %>/framework/js/util.js"></script>
<script src="<%=request.getContextPath() %>/framework/js/ScrollGrid.js"></script>
<script src="<%=request.getContextPath() %>/framework/js/leftMenu.js"></script>
<script type="text/javascript" src="<%=request.getContextPath() %>/frame/js/frame.js" charset="gb2312"></script>
<script type="text/javascript">
function submitform(){
with(document.getElementById('queryallform')){
action="ZspAction";
method="get";
submit();
}
}
</script>
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<form action="ZspAction!query.action">
<view:formtable>
            <view:formtitle name="人员查询">
             <view:buttons>
              <view:button name="查询" type="submit" onclick="submitform();"  />
            <view:button name="重置" type="reset"/>


      </view:buttons>
    </view:formtitle>

    <view:formCondition>
<view:formtr>
<view:formlabel text="账  号："></view:formlabel>
<view:forminput><input name="account" type="text"> </view:forminput>
<view:formlabel text="姓  名：" ></view:formlabel>
<view:forminput><INPUT name="name" type="text"> </view:forminput>
</view:formtr>
<view:formtr>
<view:formlabel text="生日："></view:formlabel>
<view:forminput width="20%"><view:datepicker name="stateHireDate"/></view:forminput>
<view:formlabel text="性别：" ></view:formlabel>
<view:forminput>
    男<input type="radio" checked="checked" name="sex" value="b" />
                                                                    女<input type="radio"  name="sex" value="g" /><br />

</view:forminput>
</view:formtr>
   </view:formCondition>
   </view:formtable>
</form>
</body>
</html>showresult.jsp
<%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
<%@ page import="java.util.ArrayList"%>
<%@ taglib prefix="view" uri="/WEB-INF/hollycrm-view.tld"  %>
<%@ taglib prefix="sv" uri="/WEB-INF/hollycrm-services.tld" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<%@ page import="com.hollycrm.framework.util.ToFormQueryCondition"%>
<%@page import="com.hollycrm.hollyv8.constant.CodeType"%>
<%@page import="com.hollycrm.hollyv8.zsptest.zsp.action.ZspAction"%>
<%@ page import="com.hollycrm.hollyv8.zsptest.zsp.vo.UserInfo"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<TITLE>人员增删改查</TITLE>

</head>
<body>

    <table>
      <tr>
        <td>账号</td>
        <td>姓名</td>
        <td>生日</td>
        <td>性别</td>
      </tr>
      <s:iterator value="users" >
  <tr>
  <td><s:property value="account"/></td>
  <td><s:property value="name"/></td>
  <td><s:property value="birthday"/></td>
  <td><s:property value="sex"/></td>
  <td> <s:a href="ZspAction!add.action">增加</s:a></td>
  <td><a href="ZspAction!update?id=<s:property value="account"/>">修改</a>
  <a href="ZspAction!delete?id=<s:property value="account"/>">删除</a></td>
  </tr>
  </s:iterator>
    </table>
</body>
</html>
这是结果显示页面，我刚才说错了，如果在zsp_search.jsp页面中什么都不输入，直接点查询，没有错误，如果输入点东西，就会报上面的错误。
struts+spring+Hibernate 不知道您是不是问的这个。
List<UserInfo> list = this.userDao.getUserInfo(name, account);
强制转换呢？List<UserInfo> list =（UserInfo） this.userDao.getUserInfo(name, account);
哪個jsp多少行報這個錯？你的action咋寫的？
package com.hollycrm.hollyv8.zsptest.zsp.action;import java.util.ArrayList;
import java.util.Collection;
import java.util.List;import javax.servlet.http.HttpServletRequest;import org.apache.log4j.Logger;
import org.apache.struts2.interceptor.ServletRequestAware;import com.hollycrm.framework.DefaultBeanFactory;
import com.hollycrm.hollyv8.organization.user.action.UserAction;
import com.hollycrm.hollyv8.zsptest.zsp.service.UserManagerService;
import com.hollycrm.hollyv8.zsptest.zsp.vo.UserInfo;
import com.opensymphony.xwork2.ActionSupport;public class ZspAction extends ActionSupport implements ServletRequestAware{
private HttpServletRequest request;

private static final long serialVersionUID = 8729730792551753250L;

private static Logger logger = Logger.getLogger(UserAction.class);

public void setServletRequest(HttpServletRequest request) {
this.request=request;
}
  public String ZspAction(){

     return "list_success";

       }

private UserManagerService userManager;
private List<UserInfo> users;
private UserInfo user;
// private String id;
private String account;
private String name;
private String birthday;
private String sex;
private String[] accounts;
public String[] getAccounts() {
return accounts;
} public void setAccounts(String[] accounts) {
this.accounts = accounts;
} public UserManagerService getUserManager() {
return userManager;
} public void setUserManager(UserManagerService userManager) {
this.userManager = userManager;
} public List<UserInfo> getUsers() {
return users;
} public void setUsers(List<UserInfo> users) {
this.users = users;
} public UserInfo getUser() {
return user;
} public void setUser(UserInfo user) {
this.user = user;
} /*public String getId() {
return id;
} public void setId(String id) {
this.id = id;
}*/ public String getAccount() {
return account;
} public void setAccount(String account) {
this.account = account;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public String getBirthday() {
return birthday;
} public void setBirthday(String birthday) {
this.birthday = birthday;
} public String getSex() {
return sex;
} public void setSex(String sex) {
this.sex = sex;
}

public String query1(){
users=new ArrayList<UserInfo>();
UserInfo u=new UserInfo();
u.setAccount("zhangpf");
u.setName("zhangpengfei");
u.setBirthday("1981-12-02");
u.setSex("m");
users.add(u);
return "list1_success";
}

public String query(){
users=new ArrayList<UserInfo>();
UserManagerService b=(UserManagerService) DefaultBeanFactory.getBean("UserManagerService");
if(b.getUser(account)!=null){
users.addAll((Collection<? extends UserInfo>) b);
}
return "list1_success";
}

public String add() {
  if (this.userManager.getUser(user.getName(),user.getAccount()) != null) {
   return INPUT;
  } else {
   this.userManager.addUser(user);
   return "success_add";
  } } public String list() {
  this.users = this.userManager.listUser();
  if (this.users.size() > 0) {
   return "list1_success";
//   return SUCCESS;
  } else {
   return INPUT;
  }
} public String delete() {

   if (this.account !="0" ) {
   this.userManager.deleteUser(this.account);
  } else {
   if (accounts.length > 0) {
    for (String account : accounts) {
     this.userManager.deleteUser(account);
    }
   }
  }
  if (this.userManager.listUser().size() > 0) {
  return "list1_success";
//  return SUCCESS;
  } else {
   return INPUT;
  }
}
public String saveOrUpdate() {   this.userManager.saveOrUpdate(user);
  return SUCCESS; } public String edit() {   this.user = this.userManager.getUser(account);
  return "success_edit"; } public String save() {
  String account = this.user.getAccount();
  user = this.userManager.getUser(account);
  return SUCCESS;
} public String update() {   String account = this.user.getAccount();
  this.userManager.saveOrUpdate(user);
  //return SUCCESS;
  return "success_update";
} public String login() {
  UserInfo emp = this.userManager.getUser(name, account);
  List list = this.userManager.listUser();
  if (null != emp) {
   return SUCCESS;
  } else {
   if (list.size() > 0) {
    return INPUT;
   } else {
    return ERROR;
   }
  }
}
}
你的IOC用的真是奇怪，讓人雲裏霧裏。你的錯誤在這裏： public String query(){
            users=new ArrayList<UserInfo>();
            UserManagerService b=(UserManagerService) DefaultBeanFactory.getBean("UserManagerService");
            if(b.getUser(account)!=null){
                users.addAll((Collection<? extends UserInfo>) b);
            }
            return "list1_success";
        }

users.addAll((Collection<? extends UserInfo>) b);
這一句有問題。
问题貌似出在ZspAction中的这一句可是要怎么改呢？？？
users.addAll((Collection<? extends UserInfo>) b);
public String query(){
            users=new ArrayList<UserInfo>();
            UserManagerService b=(UserManagerService) DefaultBeanFactory.getBean("UserManagerService");
            if(b.getUser(account)!=null){
                users.addAll((Collection<? extends UserInfo>) b);
            }
            return "list1_success";
        }
这一段要怎么写呢？我试了半天都不行，我是新手，请大家帮忙。
怎麽改？你的整個IOC都有問題。
你的b是UserManagerService類型，
怎麽可以強制轉換為(Collection<? extends UserInfo>)？
public String query(){
users=new ArrayList<UserInfo>();
UserManagerService b= (UserManagerService) DefaultBeanFactory.getBean("UserManagerService");
b.addUser(user);
return "list1_success";
}
我把它改成上面这样，倒是不报那个错误了，但是报另外一个错误attempt to create saveOrUpdate event with null entity我真是崭新崭新的新手，求求大家帮帮我，我快疯啦！！
user是null。你還是去看看spring 和 hibernate 基礎知識吧。
这个问题已经解决，但是现在的问题是输入的数据能够提交到数据库中，但是页面上显示不出来。我怀疑是下面的问题，不知道对不对。<s:iterator value="users" >
          <tr>
          <td><s:property value="account"/></td>
          <td><s:property value="name"/></td>
          <td><s:property value="birthday"/></td>
          <td><s:property value="sex"/></td>
          <td> <s:a href="ZspAction!add.action">增加</s:a></td>
          <td><a href="ZspAction!update?id=<s:property value="account"/>">修改</a>
          <a href="ZspAction!delete?id=<s:property value="account"/>">删除</a></td>
          </tr>
  </s:iterator>
在action中，可以用request.setAttribute("users",users);存起來