(java)java.lang.ClassCastException: java.lang.String
来源:百度知道 编辑:UC知道 时间:2024/07/03 00:41:49
public String execute() throws Exception {
TbUserDAO userDAO = new TbUserDAO();
list = userDAO.selectID();
for(int i = 0;i < list.size();i ++) {
TbUser user = list.get(i);
String id = user.getId();
System.out.println(id+"++++++++");
}
return "success";
}
在TbUser user = list.get(i);这里报java.lang.ClassCastException: java.lang.String异常
private ArrayList<TbUser> list;
TbUserDAO userDAO = new TbUserDAO();
list = userDAO.selectID();
for(int i = 0;i < list.size();i ++) {
TbUser user = list.get(i);
String id = user.getId();
System.out.println(id+"++++++++");
}
return "success";
}
在TbUser user = list.get(i);这里报java.lang.ClassCastException: java.lang.String异常
private ArrayList<TbUser> list;
TbUser user = (TbUser)list.get(i);
还有就是:
用个迭代器也不错吧?
Iterator it=list.iterator();
while(it.hasNext()){
TbUser user=(TbUser)it.next();
String userId=user.getUserId();
System.out.println(userId);
}
ClassCastException
这个异常是烈性转换异常!
你给list加个泛型!
List<TbUser> list=
这样试试看!
首先,看你这里list = userDAO.selectID();和list.get(i)是否对应。
再就是这里TbUser user =(TbUser)list.get(i);
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