<!-- pom.xml 核心依赖 -->
<dependencies>
    <!-- Spring Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- AWS SDK for S3 (天翼云ZOS兼容) -->
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-s3</artifactId>
        <version>1.12.700</version>
    </dependency>
    <!-- Lombok简化代码 -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
</dependencies>

# application.yml 配置示例
ctyun:
  oss:
    endpoint: https://your-bucket.region.ctyun.cn
    access-key: your-access-key-id
    secret-key: your-secret-access-key
    bucket-name: your-unique-bucket
    region: cn-east-1  # 根据实际区域调整

@Data
@Component
@ConfigurationProperties(prefix = "ctyun.oss")
public class CtYunOssProperties {
    private String endpoint;
    private String accessKey;
    private String secretKey;
    private String bucketName;
    private String region;
}

@Configuration
public class S3ClientConfig {
    
    @Bean
    public AmazonS3 amazonS3Client(CtYunOssProperties properties) {
        AWSCredentials credentials = new BasicAWSCredentials(
            properties.getAccessKey(), 
            properties.getSecretKey()
        );
        
        ClientConfiguration clientConfig = new ClientConfiguration()
            .withSignerOverride("S3SignerType")  // 天翼云需显式指定签名版本
            .withMaxErrorRetry(3)
            .withConnectionTimeout(5000);
        
        return AmazonS3ClientBuilder.standard()
            .withCredentials(new AWSStaticCredentialsProvider(credentials))
            .withClientConfiguration(clientConfig)
            .withEndpointConfiguration(
                new AwsClientBuilder.EndpointConfiguration(
                    properties.getEndpoint(), 
                    properties.getRegion()
                )
            )
            .build();
    }
}

@Service
@RequiredArgsConstructor
public class FileUploadService {
    private final AmazonS3 s3Client;
    private final CtYunOssProperties ossProperties;

    public String uploadFile(MultipartFile file) throws IOException {
        // 1. 文件校验
        if (file.isEmpty()) {
            throw new IllegalArgumentException("文件不能为空");
        }
        
        // 2. 生成唯一文件名（防止覆盖）
        String originalFilename = file.getOriginalFilename();
        String fileExtension = StringUtils.getFilenameExtension(originalFilename);
        String newFilename = UUID.randomUUID().toString() + 
                           (fileExtension.isEmpty() ? "" : "." + fileExtension);
        
        // 3. 上传到天翼云
        ObjectMetadata metadata = new ObjectMetadata();
        metadata.setContentType(file.getContentType());
        metadata.setContentLength(file.getSize());
        
        try (InputStream inputStream = file.getInputStream()) {
            s3Client.putObject(
                new PutObjectRequest(
                    ossProperties.getBucketName(),
                    newFilename,
                    inputStream,
                    metadata
                )
            );
        }
        
        // 4. 返回访问URL（需配置Bucket权限为公共读或生成预签名URL）
        return s3Client.getUrl(ossProperties.getBucketName(), newFilename).toString();
    }
}

@RestController
@RequestMapping("/api/files")
@RequiredArgsConstructor
public class FileUploadController {
    private final FileUploadService fileUploadService;

    @PostMapping("/upload")
    public ResponseEntity<FileUploadResponse> uploadFile(
            @RequestParam("file") MultipartFile file) {
        try {
            String fileUrl = fileUploadService.uploadFile(file);
            return ResponseEntity.ok(
                new FileUploadResponse("上传成功", fileUrl)
            );
        } catch (Exception e) {
            return ResponseEntity.badRequest()
                .body(new FileUploadResponse("上传失败: " + e.getMessage(), null));
        }
    }

    @Data
    @AllArgsConstructor
    static class FileUploadResponse {
        private String message;
        private String fileUrl;
    }
}

public String multipartUpload(MultipartFile file) throws IOException {
    // 1. 初始化分片上传
    InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(
        ossProperties.getBucketName(), file.getOriginalFilename()
    );
    InitiateMultipartUploadResult initResponse = s3Client.initiateMultipartUpload(initRequest);
    String uploadId = initResponse.getUploadId();

    // 2. 分片上传（示例：每片5MB）
    long partSize = 5 * 1024 * 1024;
    long fileLength = file.getSize();
    int partCount = (int) Math.ceil((double) fileLength / partSize);
    
    List<PartETag> partETags = new ArrayList<>();
    try (InputStream inputStream = file.getInputStream()) {
        for (int i = 1; i <= partCount; i++) {
            long startPosition = (i - 1) * partSize;
            long endPosition = Math.min(startPosition + partSize, fileLength);
            
            UploadPartRequest uploadRequest = new UploadPartRequest()
                .withBucketName(ossProperties.getBucketName())
                .withKey(file.getOriginalFilename())
                .withUploadId(uploadId)
                .withPartNumber(i)
                .withInputStream(inputStream)
                .withPartSize(endPosition - startPosition);
            
            // 注意：实际实现需处理输入流重置问题
            UploadPartResult uploadResult = s3Client.uploadPart(uploadRequest);
            partETags.add(uploadResult.getPartETag());
        }
    }

    // 3. 完成分片上传
    CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest(
        ossProperties.getBucketName(),
        file.getOriginalFilename(),
        uploadId,
        partETags
    );
    s3Client.completeMultipartUpload(compRequest);

    return s3Client.getUrl(ossProperties.getBucketName(), file.getOriginalFilename()).toString();
}

public String generatePresignedUrl(String objectKey, Duration expiration) {
    GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(
        ossProperties.getBucketName(), 
        objectKey
    )
    .withMethod(HttpMethod.GET)
    .withExpiration(Date.from(Instant.now().plus(expiration)));
    
    return s3Client.generatePresignedUrl(request).toString();
}

ExecutorService executor = Executors.newFixedThreadPool(8);
List<Future<PartETag>> futures = new ArrayList<>();

for (int i = 0; i < partCount; i++) {
    final int partNumber = i + 1;
    futures.add(executor.submit(() -> {
        // 分片上传逻辑...
        return partETag;
    }));
}

// 收集结果
List<PartETag> partETags = futures.stream()
    .map(Future::get)
    .collect(Collectors.toList());

// 示例：上传后自动触发图片审核
public String uploadWithAIProcess(MultipartFile file) {
    String fileUrl = uploadFile(file);
    
    // 调用天翼云AI服务
    AiReviewRequest reviewRequest = new AiReviewRequest()
        .withImageUrl(fileUrl)
        .withReviewTypes(Arrays.asList("porn", "terrorism"));
    
    AiReviewResult result = aiClient.reviewImage(reviewRequest);
    if (result.isViolationFound()) {
        // 自动隔离违规文件
        s3Client.setObjectAcl(ossProperties.getBucketName(), 
            file.getOriginalFilename(), 
            CannedAccessControlList.Private);
        throw new RuntimeException("文件包含违规内容");
    }
    
    return fileUrl;
}