SpringSecurity6 | 基于数据库实现登录认证

在Spring Security中，要实现基于数据库的登录认证，你需要定义一个UserDetailsService实现，该实现会根据用户名加载用户详情（包括密码和权限）。以下是一个简化的例子：

1. 创建一个实现了UserDetailsService的服务类。
2. 在该类中，根据用户名查询数据库获取用户信息。
3. 使用Spring Security提供的User类来构建用户详情。
4. 确保你的数据库查询是安全的，防止SQL注入攻击。

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;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Service;
 
@Service
public class DatabaseUserDetailsService implements UserDetailsService {
 
    private final PasswordEncoder passwordEncoder;
    // 假设你有一个用户数据访问层(UserRepository)来查询数据库
    private final UserRepository userRepository;
 
    public DatabaseUserDetailsService(PasswordEncoder passwordEncoder, UserRepository userRepository) {
        this.passwordEncoder = passwordEncoder;
        this.userRepository = userRepository;
    }
 
    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        // 从数据库查询用户信息
        YourUser user = userRepository.findByUsername(username)
            .orElseThrow(() -> new UsernameNotFoundException("User not found"));
 
        // 构建Spring Security的User对象
        return User.withUsername(user.getUsername())
                   .password(user.getPassword()) // 假设密码已经被加密
                   .authorities(user.getAuthorities())
                   .build();
    }
}

在配置Spring Security时，你需要指定这个UserDetailsService：

import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
 
@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
 
    private final DatabaseUserDetailsService userDetailsService;
 
    public SecurityC