SpringSecurity——如何编写UserDetailsService负责从数据源中加载用户信息

编写一个自定义的UserDetailsService是在Spring Security中实现用户认证的重要步骤。UserDetailsService接口负责从数据源中加载用户信息，例如用户名、密码和权限信息。

详细步骤如下 ：

1. 自定义UserDetailsService类
   创建一个名为CustomUserDetailsService的自定义UserDetailsService类，实现UserDetailsService接口：

@Service
public class CustomUserDetailsService implements UserDetailsService {
   

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
   
        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new UsernameNotFoundException("User not found with username: " + username));

        return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(),
                mapRolesToAuthorities(user.getRoles()));
    }

    private Collection<? extends GrantedAuthority> mapRolesToAuthorities(Collection<Role> roles) {
   
        return roles.stream()
                .map(role -> new SimpleGrantedAuthority(role.getName()))
                .collect(Collectors.toList());
    }
}

2. 在User实体类中定义用户信息和角色信息

@Entity
public class User {
   
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private String username;
    
    private String password;
    
    @ManyToMany(fetch = FetchType.EAGER)
    private Set<Role> roles;
    
}

3. 在Role实体类中定义角色信息

@Entity
public class Role {
   
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private String name;
    
}

4. SecurityConfig配置类

在SecurityConfig配置类中使用自定义的UserDetailsService：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
   

    @Autowired
    private CustomUserDetailsService customUserDetailsService;

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

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

通过以上步骤，可以编写一个自定义的UserDetailsService类来加载用户信息，并在Spring Security的配置类中使用该UserDetailsService来实现用户认证。这样可以实现从数据源中动态加载用户信息，提高系统的灵活性和安全性。

原文链接: https://blog.csdn.net/2401_82884096/article/details/138241259