分段复制

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分段复制是分段上传的一种特殊情况，即分段上传任务中的段通过复制OBS指定桶中现有对象（或对象的一部分）来实现。您可以通过ObsClient.copyPart来复制段。

本示例用于分段复制桶名为“sourcebucketname”里的“sourceobjectname”对象到桶名为“destbucketname”里的“destobjectname”对象。

代码示例如下所示:

// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量ACCESS_KEY_ID和SECRET_ACCESS_KEY_ID。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/intl/zh-cn/usermanual-ca/ca_01_0003.html
String ak = System.getenv("ACCESS_KEY_ID");
String sk = System.getenv("SECRET_ACCESS_KEY_ID");
String endPoint = "https://your-endpoint";
final String destBucketName = "destbucketname";
final String destObjectKey = "destobjectname";
final String sourceBucketName = "sourcebucketname";
final String sourceObjectKey = "sourceobjectname";
// 创建ObsClient实例
final ObsClient obsClient = new ObsClient(ak, sk, endPoint);

// 初始化线程池
ExecutorService executorService = Executors.newFixedThreadPool(20);

// 初始化分段上传任务
InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(destBucketName, destObjectKey);
InitiateMultipartUploadResult result = obsClient.initiateMultipartUpload(request);

final String uploadId = result.getUploadId();
Log.i("CopyPart","\t"+ uploadId + "\n");

// 获取大对象信息
ObjectMetadata metadata = obsClient.getObjectMetadata(sourceBucketName, sourceObjectKey);
// 每段复制100MB
long partSize = 100 * 1024 * 1024L;
long objectSize = metadata.getContentLength();

// 计算需要复制的段数
long partCount = objectSize % partSize == 0 ? objectSize / partSize : objectSize / partSize + 1;

final List<PartEtag> partEtags = Collections.synchronizedList(new ArrayList<PartEtag>());

// 执行并发复制段
for (int i = 0; i < partCount; i++)
{
    // 复制段起始位置
    final long rangeStart = i * partSize;
    // 复制段结束位置
    final long rangeEnd = (i + 1 == partCount) ? objectSize - 1 : rangeStart + partSize - 1;
    // 分段号
    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);
                Log.i("CopyPart","Part#" + partNumber + " done\n");
                partEtags.add(new PartEtag(result.getEtag(), result.getPartNumber()));
            }
            catch (ObsException e)
            {
                Log.e("CopyPart", e.getMessage(), e);
            }
        }
    });
}

// 等待复制完成
executorService.shutdown();
while (!executorService.isTerminated())
{
    try
    {
        executorService.awaitTermination(5, TimeUnit.SECONDS);
    }
    catch (InterruptedException e)
    {
        Log.e("CopyPart", e.getMessage(), e);
    }
}

// 合并段
CompleteMultipartUploadRequest completeMultipartUploadRequest =
    new CompleteMultipartUploadRequest(destBucketName, destObjectKey, uploadId, partEtags);
obsClient.completeMultipartUpload(completeMultipartUploadRequest);

复制段时，使用PartNumber参数指定分段号；使用UploadId参数指定分段上传任务的全局唯一标识；使用CopySource参数指定复制时的源对象信息；使用CopySourceRange参数指定待复制的源对象的字节范围。