Spring Boot中自定義Spring Security的UserDetailsService

在Spring Boot中，自定義Spring Security的UserDetailsService可以讓你實現自己的用戶認證和授權邏輯。以下是如何創建一個自定義UserDetailsService的步驟：

1. 創建一個實現UserDetailsService接口的類：

import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;

public class CustomUserDetailsService implements UserDetailsService {

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        // 在這里實現你的用戶認證邏輯
        // 例如，從數據庫或其他存儲系統中獲取用戶信息
        // 如果用戶不存在，拋出UsernameNotFoundException異常

        // 示例：從內存中加載用戶信息
        if ("admin".equals(username)) {
            return new User("admin", "password", new ArrayList<>());
        } else {
            throw new UsernameNotFoundException("User not found");
        }
    }
}

2. 在Spring Security配置類中注冊自定義UserDetailsService：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public CustomUserDetailsService customUserDetailsService() {
        return new CustomUserDetailsService();
    }

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

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

    // 其他Spring Security配置...
}

現在，你已經成功創建了一個自定義的UserDetailsService，它將在Spring Security進行用戶認證時調用。你可以根據需要修改loadUserByUsername方法以實現自己的認證邏輯。