Spring Boot+Jpa（MYSQL）做一个登陆注册系统(前后端数据库一站式编程)

spring.datasource.username=niudai
spring.datasource.password=niudai
spring.datasource.url=jdbc:mysql://localhost:3306/springdb
spring.jpa.hibernate.ddl-auto=create

package org.springframework.gsloggingdatamysql;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;
    private String name;
    private String email;
    private String password;

    @Override
    public String toString() {
        return "{" +
            " id='" + getId() + "'" +
            ", name='" + getName() + "'" +
            ", email='" + getEmail() + "'" +
            ", password='" + getPassword() + "'" +
            "}";
    }

    public String getPassword() {
        return this.password;
    }

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

    public Integer getId() {
        return this.id;
    }

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

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return this.email;
    }

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

CREATE TABLE User(id int, name varchar(255), email varchar(255), password varchar(255));

package org.springframework.gsloggingdatamysql;

import java.util.List;

import org.springframework.data.repository.CrudRepository;

public interface UserRepository extends CrudRepository<User, Integer> {
    List<User> findByEmail(String email);
    void deleteByEmail(String email);
}

package org.springframework.gsloggingdatamysql;

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {
    private static final Logger log = LoggerFactory.getLogger(UserController.class);

    @Autowired
    private UserRepository userRepository;

    @GetMapping(path="/add") // Map ONLY GET REQUESTs.
    public @ResponseBody String addNewUser (@RequestParam String name
                    , @RequestParam String email, @RequestParam String password, User user) {
        // @ResponseBody means the returned String is a response, not a view name.
        user.setName(name);
        user.setEmail(email);
        user.setPassword(password);
        userRepository.save(user);
        log.info(user.toString()+" saved to the repo");
        return "Saved";
    }

    /**
     * 登陆方法, 用户输入邮箱和密码, 查询数据库检验是否有该账户,如果有,
     * 返回原先页面 ,登陆成功。
     * @param email 用户邮箱
     * @param password 用户密码
     * @param model Spring MVC中的Model，用来储存经过controller处理后的信息，再由View层渲染
     *         得到前端页面。
     * @return
     */
    @GetMapping(path = "/login")
    public String login(@RequestParam String email, @RequestParam String password, Model model) {
        List<User> users = userRepository.findByEmail(email);
        // 如果数据库中未查到该账号:
        if (users == null) {
            log.warn("attempting to log in with the non-existed account");
            return "该用户不存在";
        } else {
            User user = users.get(0);
            if (user.getPassword().equals(password)) { 
                // 如果密码与邮箱配对成功:
                model.addAttribute("name", user.getName());
                log.warn(user.toString()+ " logged in");
            } else {
                // 如果密码与邮箱不匹配:
                model.addAttribute("name", "logging failed");
                log.warn(user.toString()+ " failed to log in");
            }
            return "index";
        }  
    }

    /**
     * 查看所有用户的注册信息，按照Spring Boot的设定，以Json的形式输送给用户端。
     * @return
     */
    @GetMapping(path="/all")
    public @ResponseBody Iterable<User> getAllUsers() {
        return userRepository.findAll();
    }

    /**
     * 域名的根目录，然后返回的“index”会映射到
     * java/resources/templates/index.html文件。
     * @param name 
     * @return
     */
    @GetMapping(path="/")
    public String welcomePage(@RequestParam(name="name", required=false, defaultValue="World")
        String namel){
            return "index";
    }


}

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <title>Spring Boot实战训练: Spring+Mysql 构建一个简单的登陆注册系统</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <link rel="stylesheet" href="index.css">
</head>

<body>
    <h2>实例驱动学习之Spring框架: </h2>
    <p>----Spring Boot+MySQL 构建一个简单的登陆注册系统</p><br>
    <p th:text="'Hello, ' + ${name} + '!'" />
    <div class="add">
        <h2>注册新账号</h2>
        <form action="/add" method="GET">
            用户名:<input type="text" name="name"><br>
            邮箱:<input type="text" name="email"><br>
            密码:<input type="password" name="password"><br>
            <input type="submit" value="注册">
        </form>
    </div>
    <div class="login">
        <h2>登陆已有账号</h2>
        <form action="/login" method="GET">
            邮箱:<input type="text" name="email"><br>
            密码:<input type="password" name="password"><br>
            <input type="submit" value="登陆">
        </form>
    </div>
    <div class="all">
        <h2><a href="/all">查看所有注册账号信息</a></h2>
    </div>
</body>

</html>