[系统运维]项目实现（1）—— 注册和登录

一. 创建动态Web工程

? ? ? 参考：https://blog.csdn.net/Archer__13/article/details/123388390?

? ? ??

? ? ?①scr目录存放自己编写的java代码，并在src下创建以下目录；

? ? ? ???

? ? ?②web目录存放web工程的资源文件，例如：html页面、css文件、js文件等，将写好的web页面放到该目录下（首页、用户登录页面、用户注册页面）；

? ? ?③WEB-INF目录是受服务器保护的目录，浏览器无法直接访问此目录的内容；

? ? ?④在WEB-INF目录下创建一个lib目录用来存放所需要的第三方jar包；

二. 创建数据库和表

? 创建一个数据库studyproject，在该数据库下创建一个user表

create table user{
    id int primary key auto_increment,
    username varchar(20) not null unique,
    password varchar(32) not null,
    email varchar(200)
};

insert into user(username,password,email) values('admin','admin','admain@163.com');

三. 编写数据库表对应的JavaBean对象

? ? ? 在pojo包下创建User类

package server.pojo;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String 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 + '\'' +
                '}';
    }

    public User() {
    }

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

四. 连接数据库（utils）

1.?创建jdbc.properties文件，将其放在src下(必须是src目录下第一级)，文件内容为：

url=jdbc:mysql://localhost:3306/studyproject   
username=root
password=123456
driverClassName=com.mysql.jdbc.Driver

initialSize=10
maxActive=10

2. 在utils包下创建一个工具类JdbcUtils.java文件，用来连接数据库

package server.utils;

import com.alibaba.druid.pool.DruidDataSourceFactory;

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

public class JdbcUtils {
    private static DataSource source;
    static{
        try {
            Properties properties = new Properties();
            //读取jdbc.properties属性
            InputStream is = JdbcUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
            //从流中加载数据
            properties.load(is);
            //创建数据库连接池
            source = DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //获取连接
    public static Connection getConnection() {
        Connection conn = null;
        try {
            conn = source.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    //关闭连接
    public static void closeResource(Connection conn){
        try {
            if(conn != null){
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

五. Dao持久层 —— 操作数据库

1. 在dao.impl包下编写BaseDao类，用来操作数据库（更新、查询）

package server.dao.impl;

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 server.utils.JdbcUtils;

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

public abstract class BaseDao {
    //使用dbutils操作数据库
    private QueryRunner queryRunner = new QueryRunner();

    //更新数据
    public int updateData(String sql, Object ... args) {
        Connection conn = JdbcUtils.getConnection();
        try {
            return queryRunner.update(conn, sql, args);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.closeResource(conn);
        }
        return -1;
    }

    //返回一条数据
    public <T> T queryOneData(Class<T> type,String sql, Object ... args){
        Connection conn = JdbcUtils.getConnection();
        try {
            return queryRunner.query(conn,sql,new BeanHandler<T>(type),args);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.closeResource(conn);
        }
        return null;
    }

    //返回多条数据
    public <T> List<T> queryList(Class<T> type, String sql, Object ... args){
        Connection conn = JdbcUtils.getConnection();
        try {
            return queryRunner.query(conn,sql,new BeanListHandler<T>(type),args);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.closeResource(conn);
        }
        return null;
    }

    //返回一个值(一行或一列)
    public Object querySingleValues(String sql, Object ... args){
        Connection conn = JdbcUtils.getConnection();
        try {
            return queryRunner.query(conn,sql,new ScalarHandler(),args);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.closeResource(conn);
        }
        return null;
    }
}

2. 在dao包下编写UserDao接口，用来查询数据库中的用户信息和将用户信息保存到数据库中

package server.dao;

import server.pojo.User;

public interface UserDao {
    //根据用户名查询用户信息，如果返回null说明没有这个用户
    public User queryUserByUsername(String username);

    //根据用户名和密码查询用户信息，如果返回null说明用户名或密码错误
    public User queryUserByUsernameAndPassword(String username,String password);

    //保存用户信息
    public int saveUser(User user);
}

?3. 在dao.impl包下编写一个UserDaoImpl类，继承BaseDao类并实现UserDao接口

package server.dao.impl;

import server.dao.UserDao;
import server.pojo.User;

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

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

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

}

六. Service业务层 —— 注册和登录

1. 在Service包下编写UserService接口，实现用户注册和登录?

package server.service;

import server.pojo.User;

public interface UserService {
    //用户注册，如果用户名已存在，则需要重新注册一个新的用户名（用户名不可以重复）
    public void registUser(User user);

    //用户登录，如果登录失败会返回null
    public User login(User user);

    //判断用户名是否存在，返回true表示用户名存在，返回flase表示用户名可用
    public boolean existUsername(String username);
}

2. 在service.impl包下编写UserServiceImpl类来实现UserService接口。

package server.service.impl;

import server.dao.UserDao;
import server.dao.impl.UserDaoImpl;
import server.pojo.User;
import server.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 existUsername(String username) {
        if(userDao.queryUserByUsername(username) == null){
            return false;
        }else {
            return true;
        }
    }
}

七. Web层 ——?实现Servlet程序

Servlet程序用于接收客户端请求然后调用Service层的服务来执行

1. 接收请求的注册信息

①在web目录下编写RegistServlet类来实现

package server.web;


import server.pojo.User;
import server.service.UserService;
import server.service.impl.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取客户端的请求
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String email = req.getParameter("email");
        String code = req.getParameter("code");

        //2.用户注册
        if(userService.existUsername(username)){
            System.out.println("用户名" + username + "已存在");
            req.getRequestDispatcher("/pages/user/regist.html").forward(req,resp);  //跳转到注册页面
        }else{
            userService.registUser(new User(null,username,password,email));
            req.getRequestDispatcher("/pages/user/regist_success.html").forward(req,resp);  //跳转到注册成功页面
            System.out.println("注册成功");
        }
    }
}

②在web.xml中配置Servlet程序的访问地址

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>RegistServlet</servlet-name>
        <servlet-class>server.web.RegistServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RegistServlet</servlet-name>
        <url-pattern>/registServlet</url-pattern>
    </servlet-mapping>
</web-app>

③在regist.html中添加Servlet程序地址（使用base标签+相对路径）

<base href="http://localhost:8080/StudyProject_war_exploded/">


<form action="registServlet" method="post">

2. 接收请求的登录信息

?①在web目录下编写RegistServlet类来实现

package server.web;

import server.pojo.User;
import server.service.UserService;
import server.service.impl.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

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

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取客户端的请求
        String username = req.getParameter("username");
        String password = req.getParameter("password");

        //2.用户登录
        User loginUser = userService.login(new User(null,username,password,null));
        if(loginUser == null){
            //登录失败，跳回登录页面
            System.out.println("失败");
            req.getRequestDispatcher("/pages/user/login.html").forward(req,resp);
        }else{
            //登录成功，跳到登录成功页面login_success.html
            System.out.println("成功");
            req.getRequestDispatcher("/pages/user/login_success.html").forward(req,resp);
        }
    }
}

②在web.xml中配置Servlet程序的访问地址

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>RegistServlet</servlet-name>
        <servlet-class>server.web.RegistServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RegistServlet</servlet-name>
        <url-pattern>/registServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>server.web.LoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/loginServlet</url-pattern>
    </servlet-mapping>
</web-app>

③在regist.html中添加Servlet程序地址（使用base标签+相对地址）

<base href="http://localhost:8080/StudyProject_war_exploded/">



<form action="loginServlet" method="post">