springboot实现登录注册

实现登录注册功能的步骤如下：

1.创建数据库表

首先要创建一个用户表，包括用户名、密码等字段。可以使用如下的 SQL 语句创建一个用户表：

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2.添加依赖

在 pom.xml 文件中添加如下依赖：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
</dependencies>

3.配置数据源

在 application.properties 文件中配置数据源：

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/dbname
spring.datasource.username=root
spring.datasource.password=password

4.实现用户实体类

创建一个 User 实体类，包含用户名、密码等属性，并为其添加 JPA 注解：

@Entity
@Table(name = "user")
public class User implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;

    // getter 和 setter 方法省略
}

5.实现用户 DAO 接口

创建一个 UserRepository 接口，继承 JpaRepository 接口，并添加一个根据用户名查找用户的方法：

public interface UserRepository extends JpaRepository<User, Long> {
    User findByUsername(String username);
}

6.实现登录功能

创建一个 LoginController 类，实现登录功能：

@Controller
public class LoginController {
    @Autowired
    private UserRepository userRepository;

    @GetMapping("/login")
    public String login() {
        return "login";
    }

    @PostMapping("/login")
    public String doLogin(@RequestParam String username, @RequestParam String password, HttpSession session) {
        User user = userRepository.findByUsername(username);
        if (user != null && user.getPassword().equals(password)) {
            session.setAttribute("user", user);
            return "redirect:/";
        } else {
            return "login";
        }
    }
}

7.实现注册功能

创建一个 RegisterController 类，实现注册功能：

@Controller
public class RegisterController {
    @Autowired
    private UserRepository userRepository;

    @GetMapping("/register")
    public String register() {
        return "register";
    }

    @PostMapping("/register")
    public String doRegister(@RequestParam String username, @RequestParam String password) {
        User user = userRepository.findByUsername(username);
        if (user == null) {
            user = new User();
            user.setUsername(username);
            user.setPassword(password);
            userRepository.save(user);
            return "redirect:/login";
        } else {
            return "register";
        }
    }
}

8.添加安全配置

在 SecurityConfig 类中添加安全配置，包括登录页面、登录处理 URL、登出 URL 等：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .antMatchers("/", "/register").permitAll()
                .anyRequest().authenticated()
                .and()
                .formLogin().loginPage("/login").defaultSuccessUrl("/")
                .and()
                .logout().logoutUrl("/logout").logoutSuccessUrl("/");
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService()).passwordEncoder(passwordEncoder());
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Override
    @Bean
    public UserDetailsService userDetailsService() {
        return new UserDetailsService() {
            @Autowired
            private UserRepository userRepository;

            @Override
            public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
                User user = userRepository.findByUsername(username);
                if (user == null) {
                    throw new UsernameNotFoundException("用户不存在");
                }
                return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());
            }
        };
    }
}

以上是基于 Spring Boot 和 Spring Security 实现登录注册功能的步骤。