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【Servlet-0】Request-用户登录案例

2022-01-22 分类：未分类 阅读(122)

用户登录案例

需求：
　1.编写login.html登录页面
　2.使用Druid数据库连接池技术，操作mysql
　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

开发步骤：
1.创建项目，导入配置文件，jar包（jar包放在WEB-INF文件夹下面的lib文件夹下面）
2.创建数据开发环境,创建数据库

  create database day14
  create table user(
	 id int primary key auto_increment,
 	 username varchar(32) unique not null,
	 password varchar(32) not null
);
desc user;

3.在ghh.domain下面创建类User
4.在ghh.dao下面创建类UserDao
5.在ghh.test下面创建类UserDaoTest
6.在ghh.servlet下面创建类LoginServlet
7.login.html中form表单的action路径的写法：虚拟目录+Serrvlet资源路径
8.在ghh.servlet下面创建类failServlet和successServlet
在这里插入图片描述
配置文件：

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3366/day14
username=root
password=root
initialSize=5
maxActive=10
maxWait=3000

login.html前端页面：

<html>

<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="http://localhost:8080/LoginServlet" method="post">
    用户名：<input type="text" name="username"><br>
    密码：<input type="password" name="password">
    <input type="submit" value="登录">
</form>
</body>
</html>

User类：封装数据库中的数据

package ghh.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 String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }

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

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

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

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

UserDao类：用于操作数据库

package ghh.dao;

import ghh.domain.User;
import ghh.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共用
    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 {
            //编写sql
            String sql = "select * from user where username=? and password=?";
            //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;
        }
    }
}

测试类：测试操作数据库的类写的正不正确

package ghh.test;

import ghh.dao.UserDao;
import ghh.domain.User;
import org.junit.Test;


public class UserDaoTest {
    @Test
    public void test() throws Exception {
        User loginuser = new User();
        loginuser.setUsername("superbaby");
        loginuser.setPassword("123");

        UserDao dao = new UserDao();
        User user = dao.login(loginuser);
        System.out.println(user);
    }
}

LoginServlet类：

package ghh.servlet;

import ghh.dao.UserDao;
import ghh.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("/LoginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //设置编码
        request.setCharacterEncoding("utf-8");
        //获取请求参数
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        //封装user对象
        User loginuser = new User();
        loginuser.setUsername(username);
        loginuser.setPassword(password);

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

        //判断User
        if(user == null){
            //登录失败
            request.getRequestDispatcher("/failServlet").forward(request,response);
        }else{
            //登录成功
            //存储数据
            request.setAttribute("user",user);
            request.getRequestDispatcher("/successServlet").forward(request,response);
        }
    }
}

failServlet：类

package ghh.servlet;

import ghh.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("/failServlet")
public class failServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //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);
    }
}

successServlet类：

package ghh.servlet;

import ghh.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对中共享的user对象
        User user = (User)request.getAttribute("user");
        if(user!=null){
            //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);
    }
}

9.BeanUtils工具类，简化数据封装
需要导入Jar包：
要求：
　1.必须被public修饰
　2.必须提供空参数的构造函数
　3.成员变量必须使用private修饰
　4.提供公共的setter和getter方法
功能：封装数据

package ghh.servlet;

import ghh.dao.UserDao;
import ghh.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 request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //设置编码
        request.setCharacterEncoding("utf-8");
//        //获取请求参数
//        String username = request.getParameter("username");
//        String password = request.getParameter("password");
//        //封装user对象
//        User loginuser = new User();
//        loginuser.setUsername(username);
//        loginuser.setPassword(password);

        //获取所有请求参数
        Map<String,String[]> map =  request.getParameterMap();
        //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();
        }

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

        //判断User
        if(user == null){
            //登录失败
            request.getRequestDispatcher("/failServlet").forward(request,response);
        }else{
            //登录成功
            //存储数据
            request.setAttribute("user",user);
            request.getRequestDispatcher("/successServlet").forward(request,response);
        }
    }
}

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