【wiki知识库】08.添加用户登录功能--后端SpringBoot部分

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;
 
import com.wikibook.core.dao.UserRepository;
import com.wikibook.core.entity.User;
 
@Service
public class UserService implements UserDetailsService {
 
    @Autowired
    private UserRepository userRepository;
 
    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByUsername(username);
        if (user == null) {
            throw new UsernameNotFoundException("User not found");
        }
        return user;
    }
}

这段代码实现了UserDetailsService接口，用于加载用户信息。当用户尝试登录时，Spring Security会调用loadUserByUsername方法来获取用户信息。如果用户不存在，则抛出UsernameNotFoundException异常。这个服务类注入了UserRepository，用于查询数据库中的用户信息。