数据读取的长度与预期不同：dataLength=964481363;

Question

我正在尝试从 S3 读取加密对象，然后将其上传到 S3 中具有不同加密密钥的新存储桶。当我尝试读取对象时，使用getObject（）并尝试使用PutObject请求放置对象。当我打印源的内容长度时，它是964481376。那么，数据长度来自哪里呢？这是964481363我的源文件的元数据如下所示：内容类型二进制/八进制流x-amz-meta-x-amz-unencrypted-content-length964481363x-amz-meta-x-amz-wrap-alg公里我无法共享 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;    }

Answer 1

我弄清楚了问题所在。S3 对象的内容长度是加密的数据长度。但是当我放置对象时，我试图放置未加密的数据。因此，我需要将对象的内容长度显式设置为未加密的长度。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;

            }