request登录案例

一、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

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <form action="/day14_test/loginServlet" 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>

二、开发步骤

1. 创建项目，导入html页面，配置文件，jar包

2. 创建数据库环境

CREATE DATABASE day14;

USE day14;

CREATE TABLE USER(

    id INT PRIMARY KEY AUTO_INCREMENT,

    username VARCHAR(32) UNIQUE NOT NULL,

     PASSWORD VARCHAR(32) NOT NULL

 );

3. 创建包cn.itcast.domain, 创建类User

package cn.itcast.domain;

/**

 * 用户的实体类

 */

public class User {

    private int id;

    private String username;

    private String password;

    public int getId() {

        return id;

    }

    public void setId(int 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 + '\'' +

                '}';

    }

}

4、4. 创建包cn.itcast.util,编写工具类JDBCUtils

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;

public class JDBCUtils {

    private static DataSource ds;

    static {

        try {

            //1.加载配置文件

            Properties pro = new Properties();

            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");

            pro.load(is);

            //2.初始化连接池对象

            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();

    }

}

5. 创建包cn.itcast.dao,创建类UserDao,提供login方法

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来对象共用

    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

    /**

     * 登录方法

     * @param loginUser 只有用户名和密码

     * @return 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.调用query方法

            User user = template.queryForObject(sql,

                    new BeanPropertyRowMapper<User>(User.class),

                    loginUser.getUsername(),

                    loginUser.getPassword());

            return user;

        } catch (DataAccessException e) {

            e.printStackTrace();

            return null;

        }

    }

}

6. 编写cn.itcast.web.servlet.LoginServlet类

package cn.itcast.web.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 {

    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user对象

        User loginUser = new User();

        loginUser.setUsername(username);

        loginUser.setPassword(password);

        */

        //2.获取所有请求参数

        Map<String, String[]> map = req.getParameterMap();

        //3.创建user对象

        User loginUser = new User();

        //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user

        if(user == null) {

            //登录失败

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

        }else {

            //登陆成功

            //存储数据

            req.setAttribute("user",user);

            //转发

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

        }

    }

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

        this.doPost(req,resp);

    }

}

7. 编写FailServlet和SuccessServlet类

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

package cn.itcast.web.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 request, HttpServletResponse response) throws ServletException, IOException {

        //给页面写一句话

        //设置编码

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

        //输出

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

    }

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

        this.doPost(request,response);

    }

}

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

package cn.itcast.web.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 request, HttpServletResponse response) throws ServletException, IOException {

        //获取request域中共享的user对象

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

        if(user != null) {

            //给页面写一句话

            //设置编码

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

            //输出

            response.getWriter().write("登录成功，"+ user.getUsername()+",欢迎您！");

        }

    }

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

        this.doPost(request,response);

    }

}

8. login.html中form表单的action路径的写法

* 虚拟目录+Servlet的资源路径

* IDEA中tocmat配置了虚拟路径

三、BeanUtils工具类

BeanUtils工具类，简化数据封装

* 用于封装JavaBean的

1. JavaBean：标准的Java类

    1. 要求：

        1. 类必须被public修饰

        2. 必须提供空参的构造器

        3. 成员变量必须使用private修饰

        4. 提供公共setter和getter方法

    2. 功能：封装数据

2. 概念：

    成员变量：

    属性：setter和getter方法截取后的产物

        例如：getUsername() --> Username--> username

3. 方法：

    1. setProperty()

    2. getProperty()

    3. populate(Object obj , Map map):将map集合的键值对信息，封装到对应的JavaBean对象中

巴特西

request登录案例

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