Jimmer-Postgresql-存储文件

create table public.sys_file
(
    id            bigint generated by default as identity primary key,
    uid           varchar(255) not null,
    original_name varchar(255) not null,
    type          varchar(255) not null,
    file_data     text[] not null,
);

类型转换器

这里直接使用 ByteArray 会出现一些稀奇古怪的错误, 例如类型为 Text[]

@Entity
@Table(name = "sys_file")
interface DataBaseFile : TenantAware {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    val id: Long

    val uid: String

    val originalName: String

    val type: FileType

    val fileData: InputStream
}

@Component
class FileScalarProvider : ScalarProvider<InputStream, ByteArray> {
override fun toScalar(sqlValue: ByteArray): InputStream {
val decompress = FileZipUtils.decompress(sqlValue)
return ByteArrayInputStream(decompress)
}

    override fun toSql(scalarValue: InputStream): ByteArray {
        val compress = FileZipUtils.compress(scalarValue.readAllBytes())
        return compress
    }
}

@ConditionalOnProperty(prefix = "file", name = ["storage"], havingValue = "database")
@Service
class DataBaseFileService(
    private val dataBaseFileRepository: DataBaseFileRepository,
) : FileService {
    /**
     * 上传图片
     * @param [multipartFile] 文件
     * @return [String]
     */
    override fun uploadFile(multipartFile: MultipartFile): String {
        if (multipartFile.size > 0) {

            val baseFile =
                new(DataBaseFile::class).by {
                    this.uid = UUID.randomUUID().toString()
                    this.originalName = multipartFile.originalFilename ?: UUID.randomUUID().toString()
                    this.type = getFileType(multipartFile)
                    this.fileData = ByteArrayInputStream(multipartFile.bytes)
                }
            dataBaseFileRepository.insert(baseFile)
            return baseFile.uid
        }
        throw EmptyFileException("文件不能为空")
    }

    /**
     * 获取文件
     * @param [fileName]
     * @return [Pair<String, ByteArray>]
     */
    override fun getFile(fileName: String): Pair<String, ByteArrayInputStream> {
        val dataBaseFile = dataBaseFileRepository.findByUid(fileName)
        return dataBaseFile.originalName to ByteArrayInputStream(dataBaseFile.fileData.readAllBytes())
    }
}


object FileZipUtils {
    const val BITE_SIZE: Int = 4 * 1024
    fun compress(data: ByteArray): ByteArray {
        val deflater = Deflater()
        deflater.setLevel(Deflater.BEST_COMPRESSION)
        deflater.setInput(data)
        deflater.finish()
        val outputStream = ByteArrayOutputStream(data.size)
        val tmp = ByteArray(BITE_SIZE)

        while (!deflater.finished()) {
            val size = deflater.deflate(tmp)
            outputStream.write(tmp, 0, size)
        }

        outputStream.close()

        return outputStream.toByteArray()
    }

    fun decompress(data: ByteArray): ByteArray {
        val inflater = Inflater()
        inflater.setInput(data)
        val outputStream = ByteArrayOutputStream(data.size)
        val tmp = ByteArray(BITE_SIZE)

        while (!inflater.finished()) {
            val count = inflater.inflate(tmp)
            outputStream.write(tmp, 0, count)
        }

        outputStream.close()

        return outputStream.toByteArray()
    }
}

/**
 * 上传文件
 * @param [file] 文件
 * @return [R<String>]
 */
@PostMapping(path = ["/upload/file"], consumes = [MediaType.MULTIPART_FORM_DATA_VALUE])
fun uploadFile(
    @RequestParam("file") file: MultipartFile,
): R<String> {
    val uploadImage = this.fileService.uploadFile(file)
    return R.success(data = uploadImage)
}

// 下载文件

@GetMapping("/download/file")
fun downloadFile(
    @RequestParam(name = "uid") uid: String,
    request: HttpServletRequest,
    response: HttpServletResponse,
) {
    val data = this.fileService.getFile(uid)
    writeFileToResponse(data.first, data.second, request, response)
}

fun writeFileToResponse(
    fileName: String,
    stream: InputStream,
    request: HttpServletRequest,
    response: HttpServletResponse,
) {
    val readAllBytes = stream.readAllBytes()
    // 设置响应头
    response.contentType = "application/octet-stream"
    response.setHeader("Content-Disposition", "attachment; filename=\"$fileName\"")
    response.setContentLength(readAllBytes.size)
    // 获取 ServletOutputStream 对象
    val servletOutputStream: OutputStream = response.outputStream
    // 直接写入数据
    servletOutputStream.write(readAllBytes)
    servletOutputStream.flush()
}