javaWeb简单登录实现验证数据库

用户登录案例需求：
1.编写login.html登录页面
username & password 两个输入框
2.使用Druid数据库连接池技术,操作mysql，day14数据库中user表
3.使用JdbcTemplate技术封装JDBC
4.登录成功跳转到SuccessServlet展示：登录成功！用户名,欢迎您
5.登录失败跳转到FailServlet展示：登录失败，用户名或密码错误

不加try(){}catch 出现了两个错误!!!!!!

java.lang.NoClassDefFoundError: org/springframework/jdbc/core/RowMappers的错误通过调试得到的

for servlet [servlet.LoginServlet] in context with path [/tom] threw excepti..............

登录实现原理就是,通过输入查询数据库,如果能的到就表示密码用户正确,否则错误,实现时可以使用try(){}catch{}

正确就返回一个对象,错误就返回null:这样就不会报错!

UserDaos

package UserDao;

import JdbcUtils.JdbcUtility;

import domain.User;

import org.springframework.dao.DataAccessException;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.JdbcTemplate;

/**

 * 操作数据库

 * @date 2019/9/22 16:42

 */

public class UserDaos {

    private JdbcTemplate templates=new JdbcTemplate(JdbcUtility.getDataSource());

    public User login(User logs){//从数据库查询用户名和密码 通过得到封装里面的数据loginuser.getUser()查找数据库对应数据

        try {//注意!!!!如果查询到了则返回user否则返回null(不会报错!!!)

            //所以依此可以判断数据库中是否存在输入的数据

            String sql="select * from log where user= ? and pass= ?";

            User user = templates.queryForObject(sql, new BeanPropertyRowMapper<>(User.class),

                    logs.getUser(),

                    logs.getPass());

            return user;

        }catch (DataAccessException e){

            e.printStackTrace();

            return null;

        }

    }

}

LoginServlet

package servlet;

import UserDao.UserDaos;

import 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("/one")

public class LoginServlet extends HttpServlet {

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

       //1.设置编码

        req.setCharacterEncoding("utf-8");

        //2.获取请求参数

        String username = req.getParameter("username");

        String password = req.getParameter("password");

        //3.封装对象

        User loginuser=new User();

        loginuser.setUser(username);

        loginuser.setPass(password);

        //4.调用userDaos

        UserDaos userDaos=new UserDaos();

        User user = userDaos.login(loginuser);

        System.out.println(user);

        //5.判断user

        if (user!=null){

            req.setAttribute("user",user);//共享数据

            req.getRequestDispatcher("/su").forward(req,resp);//重定向

        }else {

            req.getRequestDispatcher("/fa").forward(req,resp);

        }

    }

    @Override

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

    }

}

package JdbcUtils;

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;

/**

 * 数据库工具类

 * @date 2019/9/22 16:00

 */

public class JdbcUtility {

    static DataSource dataSource=null;

    static {//加载配置文件

        Properties pro=new Properties();

        InputStream rs = JdbcUtility.class.getClassLoader().getResourceAsStream("druid.properties");

        try {

            pro.load(rs);

            dataSource = DruidDataSourceFactory.createDataSource(pro);

        } catch (IOException e) {

            e.printStackTrace();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    //返回一个数据池对象

    public static DataSource getDataSource(){

        return dataSource;

    }

    //获取链接Connection对象

    public static Connection getConnection() throws SQLException {

        return dataSource.getConnection();

    }

}

user

package domain;

/**

 * s实体封装数据库表

 * @date 2019/9/22 16:40

 */

public class User {

    private int id;

    private String user;

    private String pass;

    @Override

    public String toString() {

        return "User{" +

                "id=" + id +

                ", user='" + user + '\'' +

                ", pass='" + pass + '\'' +

                '}';

    }

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getUser() {

        return user;

    }

    public void setUser(String user) {

        this.user = user;

    }

    public String getPass() {

        return pass;

    }

    public void setPass(String pass) {

        this.pass = pass;

    }

fail

package 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;

/**

 * 登录失败转发到此页面

 * @date 2019/9/22 20:47

 */

@WebServlet("/fa")

public class FailServlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //

        response.setContentType("text/html;charset=utf-8");

        //输出

        response.getWriter().write("登录失败,用户名或者密码错误");

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        this.doPost(request,response);

    }

}

sucess

package servlet;

import 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;

/**

 * 登录失败转发到此页面

 * @date 2019/9/22 20:47

 */

@WebServlet("/su")

public class SuecessServlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //

        response.setContentType("text/html;charset=utf-8");//输出为中文格式

        //输出

        User user =(User) request.getAttribute("user");

        if (user!=null){

            response.getWriter().write("登录成功,欢迎你"+user.getUser());

        }

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        this.doPost(request,response);

    }

}

html

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

<form action="/one" method="post">

    用户名:<input type="text" name="username"> <br>

    密码:<input type="password" name="password"><br>

    <input type="submit" value="登录">

</form>

</body>

</html>

数据库

DROP TABLE IF EXISTS `log`;

CREATE TABLE `log`  (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `user` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,

  `pass` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,

  PRIMARY KEY (`id`) USING BTREE

) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;

-- ----------------------------

-- Records of log

-- ----------------------------

INSERT INTO `log` VALUES (1, 'zou', '');

SET FOREIGN_KEY_CHECKS = 1;

配置文件

driverClassName=com.mysql.jdbc.Driver

url=jdbc:mysql:///login

username=root

password=123

initialSize=5

maxActive=10

maxWait=3000

巴特西

javaWeb简单登录实现验证数据库

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