三层架构 

三层架构：     

package org.entity;

public class Login {
       private int id;
       private String uname;
       private String upwd;
       public Login() {
           
       }
       public Login( String uname, String upwd) {
           
           this.uname = uname;
           this.upwd = upwd;
       }
    public Login(int id, String uname, String upwd) {
        this.id = id;
        this.uname = uname;
        this.upwd = upwd;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUname() {
        return uname;
    }
    public void setUname(String uname) {
        this.uname = uname;
    }
    public String getUpwd() {
        return upwd;
    }
    public void setUpwd(String upwd) {
        this.upwd = upwd;
    }
       
       
}
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LoginDao.jsp

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package org.dao;

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

import org.entity.Login;

//模型层，用于处理登录(查询数据)
public class LoginDao {
      public static int login(Login login) {//登录
          int flag=-1;//登录成功与否的标识  -1:系统异常，0：用户名或密码有误，1：登录成功
          int result =-1;
          Connection connection =null;
          PreparedStatement pstmt =null;
          ResultSet rs =null;
          try {
              Class.forName("com.mysql.cj.jdbc.Driver");
              //Ctrl+1自动返回
               connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/login?serverTimezone=UTC&characterEncoding=utf-8","root","vayne");
              String sql="Select count(*) from login where uname=? and upwd =?";
              pstmt = connection.prepareStatement(sql);
              pstmt.setString(1, login.getUname());
              pstmt.setString(2, login.getUpwd());
               rs = pstmt.executeQuery();
              if(rs.next()) {
                   result =rs.getInt(1);
              }
              if(result>0) {//登录成功
                  flag= 1;
              }else {
                  flag=0;//用户名或密码错误
              }
          }catch(ClassNotFoundException e) {
              e.printStackTrace();
              flag=-1;//系统异常
          }catch(SQLException e) {
              e.printStackTrace();
              flag=-1;//系统异常
          }catch(Exception e) {
              e.printStackTrace();
              flag=-1;//系统异常
          }finally {
                  try {
                      if(rs!=null) rs.close();
                      if(pstmt!=null) pstmt.close();
                      if(connection!=null) connection.close();
                  }catch(SQLException e) {
                      e.printStackTrace();
                  }catch(Exception e) {
                      e.printStackTrace();
                  }
                 
              
          }
          return flag;
      }
}
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View

login.jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录</title>
</head>
<body>
        <form action="LoginServlet" method="post">
        用户名:<input type="text" name="uname"><br/>
        密码：<input type="password" name="upwd"><br/>
        <input type="submit" value="登录"><br/>
        
        </form>
</body>
</html>
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welcome.jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
      登陆成功！！！
</body>
</html>
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Controller

 

LoginServlet.java

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package org.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.dao.LoginDao;
import org.entity.Login;

//控制器层：接受view层的请求，并分发给Model处理
public class LoginServlet extends HttpServlet {
     
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //处理登录请求    
        request.setCharacterEncoding("utf-8");
        String name= request.getParameter("uname");
        String pwd= request.getParameter("upwd");
        Login login=new Login(name,pwd);
        //调用模型层的登录功能
        int result=LoginDao.login(login);
        if(result>0) {
            request.getRequestDispatcher("welcome.jsp").forward(request, response);
        }else {//返回登录页，重新登录
            request.getRequestDispatcher("login.jsp").forward(request, response);
        }
    }

    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}
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posted @ 2021-09-24 14:22  今年哪年  阅读(38)  评论(0)    收藏  举报