The value for the useBean class attribute com.user.User is invalid.

0 0

The value for the useBean class attribute com.user.User is invalid.3

我先安装的tomcat，用myeclipse做jsp文件的时候使用<jsp:useBean id="User" scope="page" class="com.user.User" > </jsp:useBean>的时候遇到了这个问题，而且必须引入<%@page import="com.user.*"%>，否则下面用User类声明对象的时候就会出错，说User cannot be resolved to a type ，但是引入了之后运行时依然会出现 The value for the useBean class attribute com.user.User is invalid.的问题，

但是后来我用myeclipse自带的tomcat运行时就没有问题，请问这是为什么啊？

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@page language="java" contentType="text/html" pageEncoding="utf-8"%>

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<%@page import="com.user.*"%>
<%@page import="com.bean.*" %>
<%@page import="java.util.*" %>
<%@page import="java.sql.*" %>

<jsp:useBean id="User" scope="page" class="com.user.User" > </jsp:useBean>
</head>
<body>

<%
String stuNum=(String)request.getParameter("a");//获取学生学号
String stuName= new String(request.getParameter("b").getBytes("iso8859_1"),"gb2312");//获取学生姓名
out.println("dfs"+stuNum+stuName);
String checknum=(String)session.getAttribute("checknum"); //获取验证码
String pro=request.getParameter("c"); //获取用户权限未设置

session.setAttribute("stuNum",stuNum);   //创建session保存登录用户信息
session.setAttribute("stuName",stuName); //创建session保存登录用户信息
session.setAttribute("log","ok");         //创建log session 保存用户验证信息
//UserBean userBean=new UserBean();    //声明并初始化UserBean类的对象 usrBean
///userBean.setStuNum(stuNum);         //调用userBean对象的 setStuNum（）方法，为StuNum赋值
User user=new User();               //声明并初始化User类的对象user
///out.println(userBean.getStuNum());
ResultSet rs=user.selectShow(stuNum);
while(rs.next())
{
String stuNam=(String)rs.getString("stuName");
String stuDept=rs.getString("stuDept");

out.println(stuName+stuNam);
session.setAttribute("stuDept",stuDept);
if(stuNam.equals(stuName))
//out.println(stuName+stuDept);
response.sendRedirect("../main/info.jsp");
else
out.print("<script language=\"JavaScript\">alert(\"学号与姓名不匹配，请重新输入\");history.back(-1);</script>");
//out.println(stuName +stuNam );
}

%>
<script language="javascript">
alert("对不起，没有找到与该学号相匹配的信息， ");
window.location.href="login.jsp"
</script>
</body>
</html>

package com.user;

import java.io.UnsupportedEncodingException;
import java.sql.ResultSet;
import com.dbconn.*;
import com.bean.UserBean;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class User {
public User(){}
private UserBean userBean;
private Statement state;
private ResultSet resultset;
private Connection conn;
private Dbconn dbconn;
private String sql;

public ResultSet selectShow(String stuNum) { //stuNum为学生学号
// String num = this.stuNum;
// String num="2008000001";
sql = "select * from student where stuNum = '" + stuNum + "'";
dbconn=new Dbconn();
conn = dbconn.getConnection();
try {
state = conn.createStatement();
resultset = state.executeQuery(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return resultset;
}

public void updateNumbers(String stuNum,int stuCounts){
int num=Integer.parseInt(stuNum);
int counts=stuCounts+1;
dbconn=new Dbconn();
conn = dbconn.getConnection();
String sql="update student set stuCounts='"+counts+"' where stuNum='"+num+"'";
try {
state=conn.createStatement();
state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}
}

public void updateNumbers1(String stuNum,String stuCounts){
String num=stuNum;
int counts=Integer.parseInt(stuCounts)-1;
dbconn=new Dbconn();
conn = dbconn.getConnection();
String sql="update student set stuCounts='"+counts+"' where stuNum='"+num+"'";
try {
state=conn.createStatement();
state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}
}

public void setUserBean(UserBean userBean) {
this.userBean = userBean;
}

public UserBean getUserBean() {
return userBean;
}

public static void main(String[] args)
{
User use=new User();
String n="2008000001";
String cc="1";
use.updateNumbers1(n,cc);

}

}

这是jsp源码和java源码，，谢谢了，。O(∩_∩)O，。

问题补充：

高级java工程师写道

tomcat版本问题

但是为什么不开启自己安装的tomcat而是在MyEclipse里启动tomcat然后运行就没有问题，但是用自己安装的tomcat就不行，是不是tomcat没有配置好啊，我先装的jdk，配置好了，然后装的tomcat，没有配置tomcat的环境变量，直接在浏览器里就能打开猫网站，然后在tomcat根目录下改了server.xml文件，就是网上说的改了存放jsp源文件的存放路径，然后就没别的了。