8-20JDBC

最新推荐文章于 2024-07-02 09:30:00 发布

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本文详细介绍了使用Java Web技术实现的登录系统，包括User类的定义、DAO层的数据访问操作、DBUtils工具类的数据库连接、IndexServlet的请求处理及转发、重定向逻辑，以及success.jsp页面的展示。

注解配置web.xml

@WebServlet(urlPatterns = "/login")

输出快捷方式
JDBC连接测试
User

package com.pactrea.bean;

import lombok.Data;

@Data
public class User {
    private Integer id;
    private String email;
    private String password;

    public User() {
    }

    public User(Integer id, String email, String password) {
        this.id = id;
        this.email = email;
        this.password = password;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

UserDao

package com.pactrea.dao;

import com.pactrea.bean.User;
import com.pactrea.utils.DBUtils;

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

public class UserDao {
    public User getUserByEmlAndPwd(String email, String password) {
        Connection conn = DBUtils.getConnection();
        try {
            PreparedStatement preparedStatement = conn.prepareStatement("select * from user where email = ? and password = ?");
            preparedStatement.setString(1, email);
            preparedStatement.setString(2, password);
            ResultSet resultSet = preparedStatement.executeQuery();
            while (resultSet.next()) {
                User user = new User(resultSet.getInt("id"), resultSet.getString("email"), resultSet.getString("password"));
                return user;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
}

DBUtils

package com.pactrea.utils;

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

public class DBUtils {
    private static final String NAME = "root";
    private static final String PASSWORD = "";
    private static final String URL = "jdbc:mysql://localhost:3306/shopping";
    private static final String DRIVER = "com.mysql.jdbc.Driver";

    // 获取连接
    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName(DRIVER);
            conn = DriverManager.getConnection(URL, NAME, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }


}

IndexServlet

package com.pactrea.servlet;

import com.pactrea.bean.User;
import com.pactrea.dao.UserDao;

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

public class IndexServlet extends HttpServlet {
    @Override
    public void init() {

    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) {

        doPost(request, response);

//        request.setAttribute("name", "张三");
//
//        // 重定向 不带参数
////        try {
////            response.sendRedirect("jsp/index.jsp");
////        } catch (IOException e) {
////            e.printStackTrace();
////        }
//
//        // 转发 带着信息转发
//        try {
//            request.getRequestDispatcher("jsp/index.jsp").forward(request, response);
//        } catch (ServletException e) {
//            e.printStackTrace();
//        } catch (IOException e) {
//            e.printStackTrace();
//        }
    }

    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response) {
        String username = request.getParameter("email");
        String password = request.getParameter("password");
        UserDao userDao = new UserDao();
        User user = new User();
        user = userDao.getUserByEmlAndPwd(username, password);
        if (user != null) {
            try {
                request.getSession().setAttribute("currUser", user);
//                request.setAttribute("currUser2", user);
                response.sendRedirect("jsp/success.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            try {
                response.sendRedirect("jsp/login.jsp?error=yes");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

//        if (username.equals("zhangsan") && password.equals("123")) {
//            try {
//                request.setAttribute("username", username);
//                request.setAttribute("password", password);
//                request.getRequestDispatcher("jsp/success.jsp").forward(request, response);
//            } catch (IOException e) {
//                e.printStackTrace();
//            } catch (ServletException e) {
//                e.printStackTrace();
//            }
//        } else {
//            try {
////                response.sendRedirect("jsp/login.jsp?error=yes");
//                response.sendRedirect("jsp/error.jsp");
//            } catch (IOException e) {
//                e.printStackTrace();
//            }
//        }
    }

    @Override
    public void destroy() {

    }

}

success.jsp

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2019/8/19
  Time: 13:32
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>success page</title>
</head>
<body>
<h1>SUCCESS!</h1>
<%--欢迎${username},密码是${password}--%>
pageScope:${pageScope.currUser}<br>
sessionScope:${sessionScope.currUser}<br>
currUser2:${currUser2}<br>
</body>
</html>