Copying an Object - Multipart (SDK for Java)

Updated on 2024-12-11 GMT+08:00

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Function

This API allows you to upload a part by copying an object or part of this object.

You can call ObsClient.copyPart to copy parts.

NOTICE:

If you have any questions during development, post them on the Issues page of GitHub.

Restrictions

To copy an object, you must be the bucket owner or have the required permission (obs:object:PutObject in IAM or PutObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
You must have the read permission on the source object.
The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
The object copy request carries the information about the source bucket and object to be copied in the header field. The message body cannot be carried.
Cross-bucket replication in the same region is supported, but cross-region replication is not supported.
If the source object is in the Archive storage class, you must restore it first.

Method

obsClient.copyPart(CopyPartRequest request)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
request	CopyPartRequest	Yes	Explanation: Request parameters for copying an object. For details, see Table 2.

**Table 2** CopyPartRequest
Parameter	Type	Mandatory (Yes/No)	Description
sourceBucketName	String	Yes	Explanation: Name of the source bucket. Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request. Default value: None
sourceObjectKey	String	Yes	Explanation: Source object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
destinationBucketName	String	Yes	Explanation: Target bucket name. Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request. Default value: None
destinationObjectKey	String	Yes	Explanation: Target object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
byteRangeStart	Long	No	Explanation: Start position for the multipart copy Value range: A non-negative integer, in bytes. Default value: 0
byteRangeEnd	Long	No	Explanation: End position for the multipart copy Restrictions: The value must be greater than that of RangeStart. The upper limit of the value is the object length minus 1, in bytes. Value range: A non-negative integer, in bytes. Default value: None
sseCHeaderSource	SseCHeader	No	Explanation: Server-side header used for decrypting the source object. For details, see Table 3.
sseCHeaderDestination	SseCHeader	No	Explanation: Server-side encryption header used for encrypting the target object. For details, see Table 3. Restrictions: If the object uploaded to a server is encrypted with the key provided by the client, the key must also be provided in the message for downloading the object.
versionId	String	No	Explanation: Version ID of the source object, for example, G001117FCE89978B0000401205D5DC9A. If the source object has multiple versions, you can specify this parameter. Value range: The value must contain 32 characters. Default value: None
partNumber	int	Yes	Explanation: Part number. Value range: An integer ranging from 1 to 10000 Default value: None
uploadId	String	Yes	Explanation: Multipart upload ID, for example, 000001648453845DBB78F2340DD460D8. Value range: The value must contain 32 characters. Default value: None

**Table 3** SseCHeader
Parameter	Type	Mandatory (Yes/No)	Description
algorithm	ServerAlgorithm	Yes	Explanation: SSE-C is used for encrypting objects on the server side. Value range: AES256, indicating AES is used to encrypt the object in SSE-C. For details, see Table 4. Default value: None
sseAlgorithm	SSEAlgorithmEnum	No	Explanation: Encryption algorithm. Restrictions: Only AES256 is supported. Value range: See Table 5. Default value: None
sseCKey	byte[]	Yes	Explanation: Key used for encrypting the object when SSE-C is used, in byte[] format. Default value: None
sseCKeyBase64	String	No	Explanation: Base64-encoded key used for encrypting the object when SSE-C is used. Default value: None

**Table 4** ServerAlgorithm
Constant	Default Value
AES256	AES256

**Table 5** SSEAlgorithmEnum
Constant	Default Value
KMS	kms
AES256	AES256

Responses

**Table 6** CopyPartResult
Parameter	Type	Description
statusCode	int	Explanation: HTTP status code. Value range: A status code is a group of digits that can be 2xx (indicating successes) or 4xx or 5xx (indicating errors). It indicates the status of a response. For more information, see Status Code. Default value: None
responseHeaders	Map<String, Object>	Explanation: Response header list, composed of tuples. In a tuple, the String key indicates the name of the header, and the Object value indicates the value of the header. Default value: None
partNumber	int	Explanation: Part number. Value range: An integer ranging from 1 to 10000. Default value: None
etag	String	Explanation: ETag of an object, which is a Base64-encoded 128-bit MD5 digest. ETag is the unique identifier of the object content. It can be used to determine whether the object content is changed. For example, if the ETag is A when an object is uploaded and is B when the object is downloaded, the object content is changed. The ETag reflects changes only to the contents of the object, not its metadata. An object created by an upload or copy operation has a unique ETag. Restrictions: If an object is encrypted using server-side encryption, the ETag is not the MD5 value of the object. Value range: The value must contain 32 characters. Default value: None
lastModified	java.util.Date	Explanation: Last time the target part was modified. Default value: None

Code Examples

This example copies object sourceobjectname in parts from bucket sourcebucketname to bucket destbucketname as object destobjectname.

    
     
       
       import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.model.CompleteMultipartUploadRequest;
import com.obs.services.model.CopyPartRequest;
import com.obs.services.model.CopyPartResult;
import com.obs.services.model.InitiateMultipartUploadRequest;
import com.obs.services.model.InitiateMultipartUploadResult;
import com.obs.services.model.ObjectMetadata;
import com.obs.services.model.PartEtag;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class CopyPart001 {
    public static void main(String[] args) {
        // Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
        // Obtain an AK/SK pair on the management console.
        String ak = System.getenv("ACCESS_KEY_ID");
        String sk = System.getenv("SECRET_ACCESS_KEY_ID");
        // (Optional) If you are using a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding, which may result in information leakage.
        // Obtain an AK/SK pair and a security token using environment variables or import them in other ways.
        // String securityToken = System.getenv("SECURITY_TOKEN");
        // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in your actual situation.
        String endPoint = "https://obs.ap-southeast-1.myhuaweicloud.com";
        // Obtain an endpoint using environment variables or import it in other ways.
        //String endPoint = System.getenv("ENDPOINT");
        
        // Create an ObsClient instance.
        // Use the permanent AK/SK pair to initialize the client.
        ObsClient obsClient = new ObsClient(ak, sk,endPoint);
        // Use the temporary AK/SK pair and security token to initialize the client.
        // ObsClient obsClient = new ObsClient(ak, sk, securityToken, endPoint);

        try {
            // Copy parts.
            final String destBucketName = "destbucketname";
            final String destObjectKey = "destobjectname";
            final String sourceBucketName = "sourcebucketname";
            final String sourceObjectKey = "sourceobjectname";
            // Initialize the thread pool.
            ExecutorService executorService = Executors.newFixedThreadPool(20);
            // Initiate a multipart upload.
            InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(destBucketName, destObjectKey);
            InitiateMultipartUploadResult result = obsClient.initiateMultipartUpload(request);
            final String uploadId = result.getUploadId();
            System.out.println("uploadId:" + uploadId + "\n");
            // Obtain information about the large object.
            ObjectMetadata metadata = obsClient.getObjectMetadata(sourceBucketName, sourceObjectKey);
            // Set the part size to 100 MB.
            long partSize = 100 * 1024 * 1024L;
            long objectSize = metadata.getContentLength();
            // Calculate the number of parts to be copied.
            long partCount = objectSize % partSize == 0 ? objectSize / partSize : objectSize / partSize + 1;
            final List<PartEtag> partEtags = Collections.synchronizedList(new ArrayList<>());
            // Start copying parts concurrently.
            for (int i = 0; i < partCount; i++) {
                // Start position for copying parts
                final long rangeStart = i * partSize;
                // End position for copying parts
                final long rangeEnd = (i + 1 == partCount) ? objectSize - 1 : rangeStart + partSize - 1;
                // Set the part number.
                final int partNumber = i + 1;
                executorService.execute(
                        new Runnable() {
                            @Override
                            public void run() {
                                CopyPartRequest request = new CopyPartRequest();
                                request.setUploadId(uploadId);
                                request.setSourceBucketName(sourceBucketName);
                                request.setSourceObjectKey(sourceObjectKey);
                                request.setDestinationBucketName(destBucketName);
                                request.setDestinationObjectKey(destObjectKey);
                                request.setByteRangeStart(rangeStart);
                                request.setByteRangeEnd(rangeEnd);
                                request.setPartNumber(partNumber);
                                CopyPartResult result;
                                try {
                                    result = obsClient.copyPart(request);
                                    System.out.println("Part#" + partNumber + " done\n");
                                    partEtags.add(new PartEtag(result.getEtag(), result.getPartNumber()));
                                } catch (ObsException e) {
                                    e.printStackTrace();
                                }
                            }
                        });
            }
            // Wait until the copy is complete.
            executorService.shutdown();
            while (!executorService.isTerminated()) {
                try {
                    executorService.awaitTermination(5, TimeUnit.SECONDS);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            // Assemble parts.
            CompleteMultipartUploadRequest completeMultipartUploadRequest =
                    new CompleteMultipartUploadRequest(destBucketName, destObjectKey, uploadId, partEtags);
            obsClient.completeMultipartUpload(completeMultipartUploadRequest);
            System.out.println("copyObject successfully");
        } catch (ObsException e) {
            System.out.println("copyObject failed");
            // Request failed. Print the HTTP status code.
            System.out.println("HTTP Code:" + e.getResponseCode());
            // Request failed. Print the server-side error code.
            System.out.println("Error Code:" + e.getErrorCode());
            // Request failed. Print the error details.
            System.out.println("Error Message:" + e.getErrorMessage());
            // Request failed. Print the request ID.
            System.out.println("Request ID:" + e.getErrorRequestId());
            System.out.println("Host ID:" + e.getErrorHostId());
            e.printStackTrace();
        } catch (Exception e) {
            System.out.println("copyObject failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}

      

    
   