// 1. Initialize TransferService. You should use the same TransferService for the same configuration
TransferConfig transferConfig = new TransferConfig.Builder()
        .build();
TransferService transferService = new TransferService(cosXmlService, transferConfig);

// 2. Initialize PutObjectRequest
// Bucket name in the format of BucketName-APPID (APPID is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket
String bucket = "examplebucket-1250000000";
String cosPath = "exampleobject"; // Location identifier of the object in the bucket, i.e., the object key
String srcPath = "examplefilepath"; // Absolute path to the local file
PutObjectRequest putObjectRequest = new PutObjectRequest(bucket,
        cosPath, srcPath);

// 3. Call the upload method to upload the file
final COSUploadTask uploadTask = transferService.upload(putObjectRequest);
uploadTask.setCosXmlResultListener(new CosXmlResultListener() {
    @Override
    public void onSuccess(CosXmlRequest request, CosXmlResult result) {
        // You can get the CRC64 value of the file after the upload is successful
        String crc64 = result.getHeader("x-cos-hash-crc64ecma");
    }

    // If you use the Kotlin language to call this, please note that the exception in the callback method is nullable; otherwise, the onFail method will not be called back, that is:
    // clientException is of type CosXmlClientException? and serviceException is of type CosXmlServiceException?
    @Override
    public void onFail(CosXmlRequest request,
                       @Nullable CosXmlClientException clientException,
                       @Nullable CosXmlServiceException serviceException) {
        if (clientException != null) {
            clientException.printStackTrace();
        } else {
            serviceException.printStackTrace();
        }
    }
});

// 1. Initialize TransferService. You should use the same TransferService for the same configuration
TransferConfig transferConfig = new TransferConfig.Builder()
        .build();
TransferService transferService = new TransferService(cosXmlService, transferConfig);

// 2. Initialize GetObjectRequest
// Bucket name in the format of BucketName-APPID (APPID is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket
String bucket = "examplebucket-1250000000";
String cosPath = "exampleobject"; // Location identifier of the object in the bucket, i.e., the object key
String savePathDir = context.getCacheDir().toString(); // Local directory path
// File name saved locally. If not specified (null), it will be the same as the COS file name
String savedFileName = "exampleobject";
GetObjectRequest getObjectRequest = new GetObjectRequest(bucket,
        cosPath, savePathDir, savedFileName);

// 3. Call the download method to download the file
final COSDownloadTask downloadTask = transferService.download(getObjectRequest);
downloadTask.setCosXmlResultListener(new CosXmlResultListener() {
    @Override
    public void onSuccess(CosXmlRequest request, CosXmlResult result) {
        // You can get the CRC64 value of the file after the download is successful
        String cosCRC64 = result.getHeader("x-cos-hash-crc64ecma");
    }

    // If you use the Kotlin language to call this, please note that the exception in the callback method is nullable; otherwise, the onFail method will not be called back, that is:
    // clientException is of type CosXmlClientException? and serviceException is of type CosXmlServiceException?
    @Override
    public void onFail(CosXmlRequest request,
                       @Nullable CosXmlClientException clientException,
                       @Nullable CosXmlServiceException serviceException) {
        if (clientException != null) {
            clientException.printStackTrace();
        } else {
            serviceException.printStackTrace();
        }
    }
});

// 1. Refer to the above upload or download request sample code to get the CRC64 value of the file on COS
String cosCRC64 = "examplecoscrc64";

// 2. Calculate the CRC64 value of the local file
File localFile = new File("examplefilepath");
String localCRC64 = DigestUtils.getCRC64String(localFile);

// 3. Check whether localCRC64 and cosCRC64 are the same
if (localCRC64.equals(cosCRC64)) {
    // CRC64 values are the same
}