Request_登录案例_hehe.employment.over.14.5

14.8 Request_登录案例

14.8.1 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。

14.8.2 用户登录案例_分析

14.8.3 用户登录案例_代码实现

14.8.3.1 创建项目，导入html页面，导入配置文件，导入jar包（D:\CodeSoft\Install_File\lib）

• commons-logging-1.2.jar
• druid-1.0.9.jar
• mchange-commons-java-0.2.12.jar
• mysql-connector-java-5.1.37-bin.jar
• spring-beans-5.0.0.RELEASE.jar
• spring-core-5.0.0.RELEASE.jar
• spring-jdbc-5.0.0.RELEASE.jar
• spring-tx-5.0.0.RELEASE.jar

14.8.3.2 创建数据库环境

• 示例：

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
);

14.8.3.3 创建包com.xww.domain,创建类User

• 示例：

package com.xww.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 + '\'' +
                '}';
    }
}

14.8.3.4 创建包com.xww.util,编写工具类JDBCUtils

• 示例：

package com.xww.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Durid连接池
 */
public class JDBCUtils {
     

    private static DataSource ds;

    static {
     
        try {
     
        //1.加载配置文件
        Properties pro = new Properties();
        //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
        ds = DruidDataSourceFactory.createDataSource(pro);

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

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

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

14.8.3.5 创建包com.xww.dao,创建类UserDao,提供login方法

• 示例：

package com.xww.dao;

import com.xww.domain.User;
import com.xww.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());

    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();//记录日志
            return null;
        }

    }
}

14.8.3.6 编写包com.xww.web.servlet，创建LoginServlet类

• 示例：

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 {
     


    @Override
    protected void doGet(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();
        //3.2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{
     
            //登录成功
            //存储数据
            req.setAttribute("user",user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req,resp);
        }

    }

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

14.8.3.7 编写FailServlet和SuccessServlet类

• 示例：

package com.xww.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 com.xww.web.servlet;

import com.xww.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);
    }
}

14.8.3.8 login.html中form表单的action路径的写法

• 格式： 虚拟目录+Servlet的资源路径
• 示例：

<!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>

14.8.3.9 BeanUtils工具类，简化数据封装

• BeanUtils工具类： 用于封装JavaBean。
• JavaBean： 标准的Java类。
  • 要求：
    • 类必须被public修饰 ；
    • 必须提供空参的构造器 ；
    • 成员变量必须使用private修饰 ；
    • 提供公共setter和getter方法 。
  • 功能： 封装数据
• 概念：
  • 成员变量：
  • 属性： setter和getter方法截取后的产物
    • 例如： getUsername() --> Username–> username
• 方法：
  • setProperty()
  • getProperty()
  • 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。