1，打开IDEA，在src文件下创建bean包，然后在包下创建DBcon.java类

package bean;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DBcon {
    private String driverStr="com.mysql.cj.jdbc.Driver";
    private String url="jdbc:mysql://localhost:3306/letterwish";
    private String username="root";
    private String password="2001223";
    public Connection getConnction() throws ClassNotFoundException, SQLException {
            Class.forName(driverStr);
            return DriverManager.getConnection(url,username,password);
    }
}

2，jsp板块

• 创建一个login.jsp文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

  
    
      
  
  
  

      

          
LOGIN  IN
          
User Name:

          
Password:   

          

              
              
          
      
  
  
  

有login.css样式

• 创建一个checkuser.jsp文件

<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>



    


    <%
        request.setCharacterEncoding("utf-8");
        String name=request.getParameter("loginname");
        String password=request.getParameter("password");
    %>
        你输入的用户名是：<%=name%>


    <%
        Connection con=db.getConnction();
        Statement stmt=con.createStatement();
        String sql="select * from users";
        sql+= " where account='"+name+"' and pwd='"+password+"'";
        ResultSet rs=stmt.executeQuery(sql);
        if(rs.next()){
            session.setAttribute("username",name);
            response.sendRedirect("main.jsp");
        }else{
            out.print("无此用户名或密码有误，登录失败！

");
            out.print("重新登录");
        }
    %>