javabean之LoginDao

1.src中创建包org.lanqiao.dao并在包里创建LoginDao.java

2.在WEB-INF中创建check.jsp

3.check.jsp代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="org.lanqiao.dao.LoginDao" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <%
    String name = request.getParameter("uname");
    String pwd = request.getParameter("upwd");
    LoginDao dao = new LoginDao();
    int result=dao.login(name,pwd);
    if(result>0){
        out.print("登录成功");
    }else if (result==0){
        out.print("用户名或密码有误");
    }else{
        out.print("系统异常"); 
    }
    %>
</body>
</html>

4.LoginDao.jsp代码为：

package org.lanqiao.dao;
import java.sql.*;
public class LoginDao {
    public int login(String name,String pwd) {//返回1登录成功 0登录失败 -1异常
        String URL = "jdbc:mysql://localhost:3306/myemployees?serverTimezone=UTC";
         String USERNAME = "root";
         String PWD = "123456";
        
        Connection connection = null;
        Statement stmt=null; 
        ResultSet rs=null; //返回值表示增删改第几条数据
    
        try {
            //a.导入驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //b.与数据库进行连接
            connection=DriverManager.getConnection(URL,USERNAME,PWD);
            //c.发送sql,执行查找
            stmt=connection.createStatement();
            //把名字密码一收
            
             String sql="select count(*) from login where uname='"+name+"' and upwd='"+pwd+"'";

            
            
            rs=stmt.executeQuery(sql);//返回值表示增删改第几条数据
            
            //d.处理结果
            int count=-1;
            if(rs.next()) {
                count=rs.getInt(1);
            }
                if(count>0){
                    return 1;
                }
                else{
                return 0;
            }
        }catch(ClassNotFoundException e){
            e.printStackTrace();
            return -1;
            }
            catch(SQLException e) {
                e.printStackTrace();
                return -1;
            }catch(Exception e) {
                e.printStackTrace();
                return -1;
            }finally {
                try {if(rs!=null){
                    rs.close();
                }
                    if(stmt!=null) {
                        stmt.close();
                    }if(connection!=null) {
                        connection.close();
                    }
                }catch(SQLException e) {
                    e.printStackTrace();
                }
            }
    }

}

5.如果遇到MyWebProject打着叉子

 

进入　BuildPath，将打叉的移除即可

 

posted @ 2020-07-06 23:22  风度"  阅读(228)  评论(0)    收藏  举报