数据库实体与本地文件同步删除策略：最佳实践与风险规避

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Optional;

@Service
public class ChannelService {

    private final ChannelRepository channelRepository;
    private final String uploadDir = "/path/to/your/avatar/storage/"; // 你的文件存储路径

    public ChannelService(ChannelRepository channelRepository) {
        this.channelRepository = channelRepository;
    }

    @Transactional
    public void deleteChannelAndAvatar(Long channelId) {
        Optional<Channel> channelOptional = channelRepository.findById(channelId);

        if (channelOptional.isPresent()) {
            Channel channel = channelOptional.get();
            String avatarPath = channel.getAvatarPath(); // 假设Channel实体有getAvatarPath方法

            // 1. 先删除数据库实体
            channelRepository.delete(channel);

            // 2. 后删除本地文件
            if (avatarPath != null && !avatarPath.isEmpty()) {
                try {
                    Path filePath = Paths.get(uploadDir, avatarPath);
                    if (Files.exists(filePath)) {
                        Files.delete(filePath);
                        System.out.println("Deleted local avatar file: " + filePath);
                    }
                } catch (IOException e) {
                    // 文件删除失败，事务将回滚，数据库实体不会被删除
                    System.err.println("Failed to delete local avatar file: " + avatarPath + ", error: " + e.getMessage());
                    throw new RuntimeException("Failed to delete local avatar file", e);
                }
            }
        } else {
            throw new IllegalArgumentException("Channel with ID " + channelId + " not found.");
        }
    }
}

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@Component
public class OrphanedFileCleanupScheduler {

    private final ChannelRepository channelRepository;
    private final String uploadDir = "/path/to/your/avatar/storage/"; // 你的文件存储路径

    public OrphanedFileCleanupScheduler(ChannelRepository channelRepository) {
        this.channelRepository = channelRepository;
    }

    // 每小时执行一次，清理孤儿文件
    @Scheduled(fixedRate = 3600000) // 1 hour in milliseconds
    public void cleanupOrphanedAvatars() {
        System.out.println("Starting orphaned avatar cleanup job...");

        try {
            // 1. 获取数据库中所有被引用的头像路径
            Set<String> referencedAvatarPaths = channelRepository.findAll()
                                                                 .stream()
                                                                 .map(Channel::getAvatarPath)
                                                                 .filter(path -> path != null && !path.isEmpty())
                                                                 .collect(Collectors.toSet());

            // 2. 遍历本地文件系统中的头像文件
            Path dirPath = Paths.get(uploadDir);
            if (Files.exists(dirPath) && Files.isDirectory(dirPath)) {
                try (Stream<Path> files = Files.list(dirPath)) {
                    files.forEach(filePath -> {
                        String fileName = filePath.getFileName().toString();
                        // 3. 比对并删除孤儿文件
                        if (!referencedAvatarPaths.contains(fileName)) {
                            try {
                                Files.delete(filePath);
                                System.out.println("Deleted orphaned avatar file: " + filePath);
                            } catch (IOException e) {
                                System.err.println("Failed to delete orphaned avatar file: " + filePath + ", error: " + e.getMessage());
                            }
                        }
                    });
                }
            }
        } catch (IOException e) {
            System.err.println("Error during orphaned avatar cleanup: " + e.getMessage());
        }
        System.out.println("Orphaned avatar cleanup job finished.");
    }
}