使用Druid连接池实现用户的登录

程序员文章站 2022-06-28 13:32:22

使用Druid连接池实现用户登录：工程结构： dao：UserDaopackage cn.itcast.dao;import cn.itcast.domain.User;import cn.itcast.util.JDBCUtils;import org.springframework.dao.DataAccessException;import org.springframework.jdbc.core.BeanPropertyRowMapper;i......

使用Druid连接池实现用户登录：

工程结构：

使用Druid连接池实现用户的登录

dao：UserDao

package cn.itcast.dao;

import cn.itcast.domain.User;
import cn.itcast.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

/**
 * 操作数据库中User表的类
 */
public class UserDao {

    //声明JDBCTemplate对象共用
    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

    /**
     * 登录方法
     *
     * @param loginUser 只有用户名和密码
     * @return user 包含用户全部数据
     */
    public User login(User loginUser) {

        try {
            //1. 编写sql
            String sql = "select * from user where username = ? and password = ? ";
            //2.执行
            User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class),
                    loginUser.getUsername(), loginUser.getPassword());

            return user;

        } catch (DataAccessException e) {
            e.printStackTrace();
            return null;
        }

    }
}

domain : User

package cn.itcast.domain;

public class User {
    private Integer id; //用户id
    private String username; //账号
    private String password; //密码

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

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

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

servlet:

LoginServlet

package cn.itcast.servlet;

import cn.itcast.dao.UserDao;
import cn.itcast.domain.User;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;


@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //1.设置编码
        req.setCharacterEncoding("utf-8");

      /*  //2.获取对象
        String username = req.getParameter("username");
        String password = req.getParameter("password");

        //3.封装user对象
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);*/

        //2.获取所有的参数
        Map<String, String[]> map = req.getParameterMap();
        //3.创建User对象
        User loginUser = new User();
        //3.1 使用BeanUtils封装
        try {

            BeanUtils.populate(loginUser, map);

        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        //4.调用UserDao的login方法
        UserDao dao = new UserDao();
        User user = dao.login(loginUser);

        //5.判断查询结果
        if (user != null) {
            //登录成功
            //存储数据
            req.setAttribute("user", user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req, resp);
        } else {
            //登录失败。账号密码错误
            req.getRequestDispatcher("/failServlet").forward(req, resp);

        }

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }
}

successServlet:

package cn.itcast.servlet;

import cn.itcast.domain.User;

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

@WebServlet("/successServlet")
public class SuccessServlet extends HttpServlet {
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        //给页面写一句话

        //获取数据
        User user = (User) req.getAttribute("user");

        if (user != null) {
            //设置编码
            resp.setContentType("text/html;charset=utf-8");
            resp.getWriter().write("登录成功，" + user.getUsername() + "欢迎你");
        }

    }

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}

failServlet:

package cn.itcast.servlet;

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

@WebServlet("/failServlet")
public class FailServlet extends HttpServlet {
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //给页面写一句话

        //设置编码
        resp.setContentType("text/html;charset=utf-8");
        resp.getWriter().write("登录失败，用户名或密码错误");
    }

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}

util:

JDBCUtils:工具类

package cn.itcast.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

/**
 * JDBC工具类，使用Druid连接池
 */
public class JDBCUtils {

    private static DataSource ds;

    static {

        try {
            //1.加载配置文件
            Properties pro = new Properties();
            //2.使用classloader加载配置文件，获取字节输入流
            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(is);

            //2. 初始化连接池对象 Statement
            ds = DruidDataSourceFactory.createDataSource(pro);

        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取连接池对象
     */
    public static DataSource getDataSource() {
        return ds;
    }


    /**
     * 获取连接Connection对象
     */
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }

}

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        <form action="/test/loginServlet" method="post">
            用户名： <input type="text" name="username">
            密码： <input type="password" name="password">

            <input type="submit" value="提交">

        </form>

    </body>
</html>

数据库SQL：

使用Druid连接池实现用户的登录

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `PASSWORD` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE INDEX `username`(`username`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, 'zhangsan', '123');

SET FOREIGN_KEY_CHECKS = 1;

本文地址：https://blog.csdn.net/qq_41144160/article/details/110187568

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