读取的数据与预期的长度不同:DataLength=964481363；预期长度=964481376；

Question

我正在尝试从S3读取一个加密对象，然后用不同的加密密钥将其上传到S3中的一个新bucket中。而我正在尝试使用getObject（）读取对象,并尝试使用PutObject请求放置对象。

当我打印源代码的内容长度时，它是964481376。那么，数据长度从何而来？是964481363

内容类型

二进制/二进制八位数流

x-amz-元-x-amz-未加密-内容-长度

我不能共享KMS密钥。

public boolean copyS3Object(AmazonS3Encryption sourceS3Client, AmazonS3URI sourceS3Uri,
            AmazonS3Encryption destS3Client, AmazonS3URI destS3Uri) throws AmazonServiceException, IOException {
        //String eTag;
        S3Object sourceS3Object = null;

        try {
            //Get the Source object stream
            sourceS3Object = sourceS3Client.getObject(sourceS3Uri.getBucket(), sourceS3Uri.getKey());
            ObjectMetadata objectMetadata = sourceS3Object.getObjectMetadata();
            System.out.println("content length " + objectMetadata.getContentLength());
            PutObjectRequest putRequest = new PutObjectRequest(destS3Uri.getBucket(), destS3Uri.getKey(),
                    sourceS3Object.getObjectContent(), sourceS3Object.getObjectMetadata());

            destS3Client.putObject(putRequest);
//
//            if (eTag.isEmpty()) {
//                System.out.println("Copy failed, New object in " + destS3Uri.toString() + " is empty");
//                return false;
//            }

        } catch (AmazonServiceException e) {
            throw e;
        } finally {
            if (sourceS3Object != null) {
                sourceS3Object.close();
            }
        }
        //System.out.println("Copied successfully to " + destS3Uri.toString() + " Etag:" + eTag);
        return true;
    }

但我得到以下错误：

Answer 1

我想出了问题所在。S3对象的内容长度是加密后的数据长度。但当我放置对象时，我正在尝试放置未加密的数据。所以我需要显式地将对象的内容长度设置为未加密长度。下面的代码解决了这个问题。

 try {
            //Get the Source object stream
            sourceS3Object = sourceS3Client.getObject(sourceS3Uri.getBucket(), sourceS3Uri.getKey());
            //For a decrypted object, the content length in metadata has the encrypted length
            //Set the content length to the unencrypted-data-length
            ObjectMetadata objectMetadata = sourceS3Object.getObjectMetadata();
            Map<String, String> modelMetaData = objectMetadata.getUserMetadata();
            Long unencryptedDataLength = Long.parseLong(modelMetaData.get(
                    "x-amz-unencrypted-content-length"));
            objectMetadata.setContentLength(unencryptedDataLength);
            PutObjectRequest putRequest = new PutObjectRequest(destS3Uri.getBucket(), destS3Uri.getKey(),
                    sourceS3Object.getObjectContent(), objectMetadata);

            eTag = destS3Client.putObject(putRequest).getETag();

            if (eTag.isEmpty()) {
                System.out.println("Copy failed, New object in " + destS3Uri.toString() + " is empty");
                return false;
            }