书城项目第二阶段——用户注册和登录功能的实现

JavaEE的三层架构

第一步：搭建项目环境

项目基本框架：

分层的目的是为了解耦。解耦就是为了降低代码的耦合度。方便项目后期的维护和升级。

测试包
com.ftn.test/junit
工具类
com.atguigu.utils
实体bean对象
com.ftn.pojo/entity/domain/bean： JavaBean类
dao持久层
com.ftn.dao： Dao接口包
com.ftn.daoImpl： Dao接口实现类
service层
com.ftn.service： Service接口包
com.ftn.serviceImpl： Service接口实现类
web层
com.ftn.web: 实现功能的servlet类

第二步：创建数据库和t_user用户表

第三步：编写数据库表对应的JavaBean对象

package com.ftn.pojo;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String email;

    public User() {
    }

    public User(Integer id, String username, String password, String email) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.email = email;
    }

    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;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

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

第四步：编写工具类 JdbcUtils

将获取数据库的连接以及关闭数据库的连接（放回数据库连接池）操作封装为一个工具类
(在这里有一个需要注意的点：druid的配置文件druid.proerties需要放置在resource文件夹中，不然无法读取到它)

package com.ftn.utils;

import com.alibaba.druid.pool.DruidDataSourceFactory;

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

public class JdbcUtils {
    private static DataSource dataSource;

    static {
        Properties properties = new Properties();
        try {
            InputStream resourceAsStream = JdbcUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            properties.load(resourceAsStream);
            dataSource = DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }

    public static void close(ResultSet set, PreparedStatement statement,Connection connection){
        try {
            if (set!=null){
                set.close();
            }
            if (statement!=null){
                statement.close();
            }
            if (connection!=null){
                connection.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

第五步：编写BasicDao

将数据库的update操作和query操作封装至BasicDao类中

package com.ftn.dao;

import com.ftn.utils.JdbcUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

public abstract class BasicDao {
    private QueryRunner queryRunner = new QueryRunner();

    public int query_update(String sql,Object... args){
        Connection connection = null;
        try {
            connection = JdbcUtils.getConnection();
            return queryRunner.update(connection,sql,args);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            JdbcUtils.close(null,null, connection);
        }
    }

    public List query_multi(String sql, Class clazz, Object... args){
        Connection connection = null;
        try {
            connection = JdbcUtils.getConnection();
            return queryRunner.query(connection,sql,new BeanListHandler(clazz),args);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            JdbcUtils.close(null,null,connection);
        }
    }

    public T query_single(String sql,Class clazz,Object... args){
        Connection connection = null;
        try {
            connection = JdbcUtils.getConnection();
            return queryRunner.query(connection,sql,new BeanHandler(clazz),args);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            JdbcUtils.close(null,null,connection);
        }
    }

    public Object query_scalar(String sql,Object... args){
        Connection connection = null;
        try {
            connection = JdbcUtils.getConnection();
            return queryRunner.query(connection,sql,new ScalarHandler<>(),args);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            JdbcUtils.close(null,null,connection);
        }
    }
}

第六步：编写UserDao及UserDaoImpl

UserDao接口需要实现的功能：

通过用户名查找用户
通过用户名和密码查找用户
保存用户到数据库

package com.ftn.dao;

import com.ftn.pojo.User;

public interface UserDao {
    
    public User queryUserByUsername(String username);

    
    public User queryUserByUsernameAndPassword(String username,String password);

    
    public int saveUser(User user);
}

UserDaoImpl

package com.ftn.daoImpl;

import com.ftn.dao.BasicDao;
import com.ftn.dao.UserDao;
import com.ftn.pojo.User;

public class UserDaoImpl extends BasicDao implements UserDao {
    @Override
    public User queryUserByUsername(String username) {
        String sql = "select id,username,password,email from t_user where username=?";
        return query_single(sql,User.class,username);
    }

    @Override
    public User queryUserByUsernameAndPassword(String username, String password) {
        String sql = "select id,username,password,email from t_user where username=? and password=?";
        return query_single(sql,User.class,username,password);
    }

    @Override
    public int saveUser(User user) {
        String sql = "insert into t_user(`username`,`password`,`email`) values(?,?,?)";
        return query_update(sql,user.getUsername(),user.getPassword(),user.getEmail());
    }
}

第七步：编写UserService和UserServiceImpl

UserService接口需要实现的功能：

注册
登录
检查用户名是否可用

package com.ftn.service;

import com.ftn.pojo.User;

public interface UserService {
    
    public void registUser(User user);

    
    public User login(User user);

    
    public boolean existsUsername(String username);
}

UserServiceImpl

package com.ftn.serviceImpl;

import com.ftn.dao.UserDao;
import com.ftn.daoImpl.UserDaoImpl;
import com.ftn.pojo.User;
import com.ftn.service.UserService;

public class UserServiceImpl implements UserService {
    private UserDao userDao = new UserDaoImpl();

    @Override
    public void registUser(User user) {
        userDao.saveUser(user);
    }

    @Override
    public User login(User user) {
        return userDao.queryUserByUsernameAndPassword(user.getUsername(),user.getPassword());
    }

    @Override
    public boolean existsUsername(String username) {
        return userDao.queryUserByUsername(username)!=null;
    }
}

第八步：实现用户注册的功能

（使用base标签加相对路径的方式来设置路径）
使用Post请求更安全

package com.ftn.web;

import com.ftn.pojo.User;
import com.ftn.service.UserService;
import com.ftn.serviceImpl.UserServiceImpl;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;

public class RegistServlet extends HttpServlet {
    private UserService userService = new UserServiceImpl();

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

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1、获取请求的参数
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String email = request.getParameter("email");
        String code = request.getParameter("code");
//        2、检查验证码是否正确 == 先写死，要求为：abcde，忽略大小写
        if ("abcde".equalsIgnoreCase(code)){
//        正确
//        3、检查用户名是否可用
            if (!userService.existsUsername(username)){
//        可用

//        4、调用Service保存到数据库
                userService.registUser(new User(null,username,password,email));
//        5、跳到注册成功页面regist_success.html
                request.getRequestDispatcher("/pages/user/regist_success.html").forward(request,response);
            }else {
//        不可用
                System.out.println("用户名已存在");
                request.getRequestDispatcher("/pages/user/regist.html").forward(request,response);
//        跳回注册页面
            }
        }else {
//        不正确
            System.out.println("验证码错误");
            request.getRequestDispatcher("/pages/user/regist.html").forward(request,response);
//        跳回注册页面
        }
    }
}

第九步：用户登录功能的实现

package com.ftn.web;

import com.ftn.pojo.User;
import com.ftn.service.UserService;
import com.ftn.serviceImpl.UserServiceImpl;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;

public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1，获取请求的参数
        String username = request.getParameter("username");
        String password = request.getParameter("password");
//        2，调用Userservice.login()处理业务userservice.Login()登录
        UserService userService = new UserServiceImpl();
//        3，根据Login()方法返回结果判断登录是否成功
        if (userService.login(new User(null,username,password,null))!=null){
//                成功
            request.getRequestDispatcher("/pages/user/login_success.html").forward(request,response);
//        跳到成功页面Login_success.html
        }else {
//                失败
            System.out.println("用户未注册，请先注册");
            request.getRequestDispatcher("/pages/user/login.html").forward(request,response);
//        跳回登录页面
        }
    }
}

书城项目第二阶段——用户注册和登录功能的实现

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