数据库实体删除时同步清理本地文件的策略与实践

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.io.File;
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; // 假设有一个ChannelRepository
    private final String uploadDir; // 文件上传的根目录

    public ChannelService(ChannelRepository channelRepository, @Value("${app.upload.dir}") String uploadDir) {
        this.channelRepository = channelRepository;
        this.uploadDir = uploadDir;
    }

    @Transactional // 确保数据库和文件操作在同一个事务中
    public void deleteChannelAndAvatar(Long channelId) {
        Optional<Channel> channelOptional = channelRepository.findById(channelId);
        if (channelOptional.isEmpty()) {
            throw new IllegalArgumentException("Channel not found with ID: " + channelId);
        }
        Channel channel = channelOptional.get();

        // 1. 从数据库中删除Channel实体
        channelRepository.delete(channel);

        // 2. 删除本地磁盘上的头像文件
        String avatarPath = channel.getAvatarPath(); // 假设Channel实体有getAvatarPath()方法
        if (avatarPath != null && !avatarPath.trim().isEmpty()) {
            // 拼接完整的文件路径
            Path fullPath = Paths.get(uploadDir, avatarPath);
            File avatarFile = fullPath.toFile();

            if (avatarFile.exists() && avatarFile.isFile()) {
                try {
                    Files.delete(fullPath);
                    System.out.println("成功删除头像文件: " + fullPath.toString());
                } catch (IOException e) {
                    // 文件删除失败，记录日志。根据业务需求决定是否抛出异常以回滚数据库事务
                    System.err.println("删除头像文件失败: " + fullPath.toString() + ", 错误: " + e.getMessage());
                    // 如果文件删除是强制性的，应抛出异常以触发事务回滚
                    throw new RuntimeException("Failed to delete associated avatar file", e);
                }
            } else {
                System.out.println("头像文件不存在或不是文件: " + fullPath.toString());
            }
        } else {
            System.out.println("Channel ID: " + channelId + " 没有关联的头像路径。");
        }
    }
}

// 假设的Channel实体和Repository接口
class Channel {
    private Long id;
    private String name;
    private String avatarPath; // 存储相对路径
    // Getters and Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public String getAvatarPath() { return avatarPath; }
    public void setAvatarPath(String avatarPath) { this.avatarPath = avatarPath; }
}

interface ChannelRepository extends org.springframework.data.repository.CrudRepository<Channel, Long> {
}