# 使用适用于 Java 的 SDK 执行和管理分段上传
<a name="S3OutpostsMPU"></a>

使用 Amazon S3 on Outposts，您可以在 Amazon Outposts 资源上创建 S3 存储桶，并在本地为需要本地数据访问、本地数据处理和数据驻留的应用程序存储和检索对象。您可以通过 Amazon Web Services 管理控制台、Amazon Command Line Interface (Amazon CLI)、Amazon SDK 或 REST API 使用 S3 on Outposts。有关更多信息，请参阅 [什么是 Amazon S3 on Outposts？](S3onOutposts.md) 

以下示例显示如何结合使用 S3 on Outposts 和 适用于 Java 的 Amazon SDK 来执行和管理分段上传。

**Topics**
+ [在 S3 on Outposts 存储桶中执行对象的分段上传](#S3OutpostsInitiateMultipartUploadJava)
+ [通过分段上传，在 S3 on Outposts 存储桶中复制大型对象](#S3OutpostsCopyPartJava)
+ [在 S3 on Outposts 存储桶中列出对象的分段](#S3OutpostsListPartsJava)
+ [检索 S3 on Outposts 存储桶中正在进行的分段上传的列表](#S3OutpostsListMultipartUploadsJava)

## 在 S3 on Outposts 存储桶中执行对象的分段上传
<a name="S3OutpostsInitiateMultipartUploadJava"></a>

以下 S3 on Outposts 示例使用适用于 Java 的 SDK 启动、上传和完成对象到存储桶的分段上传。要使用此示例，请将每个 `user input placeholder` 替换为您自己的信息。有关更多信息，请参阅《Amazon Simple Storage Service 用户指南》**中的[使用分段上传操作上传对象](https://docs.amazonaws.cn/AmazonS3/latest/userguide/mpu-upload-object.html)。

```
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.*;

import java.util.ArrayList;
import java.util.List;

public class MultipartUploadCopy {
    public static void main(String[] args) {
        String accessPointArn = "*** Source access point ARN ***";
        String sourceObjectKey = "*** Source object key ***";
        String destObjectKey = "*** Target object key ***";

        try {
            // This code expects that you have Amazon credentials set up per:
            // https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/setup-credentials.html
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .enableUseArnRegion()
                    .build();

            // Initiate the multipart upload.
            InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(accessPointArn, destObjectKey);
            InitiateMultipartUploadResult initResult = s3Client.initiateMultipartUpload(initRequest);

            // Get the object size to track the end of the copy operation.
            GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest(accessPointArn, sourceObjectKey);
            ObjectMetadata metadataResult = s3Client.getObjectMetadata(metadataRequest);
            long objectSize = metadataResult.getContentLength();

            // Copy the object using 5 MB parts.
            long partSize = 5 * 1024 * 1024;
            long bytePosition = 0;
            int partNum = 1;
            List<CopyPartResult> copyResponses = new ArrayList<CopyPartResult>();
            while (bytePosition < objectSize) {
                // The last part might be smaller than partSize, so check to make sure
                // that lastByte isn't beyond the end of the object.
                long lastByte = Math.min(bytePosition + partSize - 1, objectSize - 1);

                // Copy this part.
                CopyPartRequest copyRequest = new CopyPartRequest()
                        .withSourceBucketName(accessPointArn)
                        .withSourceKey(sourceObjectKey)
                        .withDestinationBucketName(accessPointArn)
                        .withDestinationKey(destObjectKey)
                        .withUploadId(initResult.getUploadId())
                        .withFirstByte(bytePosition)
                        .withLastByte(lastByte)
                        .withPartNumber(partNum++);
                copyResponses.add(s3Client.copyPart(copyRequest));
                bytePosition += partSize;
            }

            // Complete the upload request to concatenate all uploaded parts and make the copied object available.
            CompleteMultipartUploadRequest completeRequest = new CompleteMultipartUploadRequest(
                    accessPointArn,
                    destObjectKey,
                    initResult.getUploadId(),
                    getETags(copyResponses));
            s3Client.completeMultipartUpload(completeRequest);
            System.out.println("Multipart copy complete.");
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process 
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client  
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }

    // This is a helper function to construct a list of ETags.
    private static List<PartETag> getETags(List<CopyPartResult> responses) {
        List<PartETag> etags = new ArrayList<PartETag>();
        for (CopyPartResult response : responses) {
            etags.add(new PartETag(response.getPartNumber(), response.getETag()));
        }
        return etags;
    }
```

## 通过分段上传，在 S3 on Outposts 存储桶中复制大型对象
<a name="S3OutpostsCopyPartJava"></a>

下面的 S3 on Outposts 示例使用适用于 Java 的 SDK 复制存储桶中的对象。要使用此示例，请将每个 `user input placeholder` 替换为您自己的信息。

```
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.*;

import java.util.ArrayList;
import java.util.List;

public class MultipartUploadCopy {
    public static void main(String[] args) {
        String accessPointArn = "*** Source access point ARN ***";
        String sourceObjectKey = "*** Source object key ***";
        String destObjectKey = "*** Target object key ***";

        try {
            // This code expects that you have Amazon credentials set up per:
            // https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/setup-credentials.html
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .enableUseArnRegion()
                    .build();

            // Initiate the multipart upload.
            InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(accessPointArn, destObjectKey);
            InitiateMultipartUploadResult initResult = s3Client.initiateMultipartUpload(initRequest);

            // Get the object size to track the end of the copy operation.
            GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest(accessPointArn, sourceObjectKey);
            ObjectMetadata metadataResult = s3Client.getObjectMetadata(metadataRequest);
            long objectSize = metadataResult.getContentLength();

            // Copy the object using 5 MB parts.
            long partSize = 5 * 1024 * 1024;
            long bytePosition = 0;
            int partNum = 1;
            List<CopyPartResult> copyResponses = new ArrayList<CopyPartResult>();
            while (bytePosition < objectSize) {
                // The last part might be smaller than partSize, so check to make sure
                // that lastByte isn't beyond the end of the object.
                long lastByte = Math.min(bytePosition + partSize - 1, objectSize - 1);

                // Copy this part.
                CopyPartRequest copyRequest = new CopyPartRequest()
                        .withSourceBucketName(accessPointArn)
                        .withSourceKey(sourceObjectKey)
                        .withDestinationBucketName(accessPointArn)
                        .withDestinationKey(destObjectKey)
                        .withUploadId(initResult.getUploadId())
                        .withFirstByte(bytePosition)
                        .withLastByte(lastByte)
                        .withPartNumber(partNum++);
                copyResponses.add(s3Client.copyPart(copyRequest));
                bytePosition += partSize;
            }

            // Complete the upload request to concatenate all uploaded parts and make the copied object available.
            CompleteMultipartUploadRequest completeRequest = new CompleteMultipartUploadRequest(
                    accessPointArn,
                    destObjectKey,
                    initResult.getUploadId(),
                    getETags(copyResponses));
            s3Client.completeMultipartUpload(completeRequest);
            System.out.println("Multipart copy complete.");
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process 
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client  
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }

    // This is a helper function to construct a list of ETags.
    private static List<PartETag> getETags(List<CopyPartResult> responses) {
        List<PartETag> etags = new ArrayList<PartETag>();
        for (CopyPartResult response : responses) {
            etags.add(new PartETag(response.getPartNumber(), response.getETag()));
        }
        return etags;
    }
}
```

## 在 S3 on Outposts 存储桶中列出对象的分段
<a name="S3OutpostsListPartsJava"></a>

以下 S3 on Outposts 示例使用适用于 Java 的 SDK 列出存储桶中对象的分段。要使用此示例，请将每个 `user input placeholder` 替换为您自己的信息。

```
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.*;

import java.util.List;

public class ListParts {
    public static void main(String[] args) {
        String accessPointArn = "*** access point ARN ***";
        String keyName = "*** Key name ***";
        String uploadId = "*** Upload ID ***";

        try {
            // This code expects that you have Amazon credentials set up per:
            // https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/setup-credentials.html
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .enableUseArnRegion()
                    .build();

            ListPartsRequest listPartsRequest = new ListPartsRequest(accessPointArn, keyName, uploadId);
            PartListing partListing = s3Client.listParts(listPartsRequest);
            List<PartSummary> partSummaries = partListing.getParts();

            System.out.println(partSummaries.size() + " multipart upload parts");
            for (PartSummary p : partSummaries) {
                System.out.println("Upload part: Part number = \"" + p.getPartNumber() + "\", ETag = " + p.getETag());
            }

        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}
```

## 检索 S3 on Outposts 存储桶中正在进行的分段上传的列表
<a name="S3OutpostsListMultipartUploadsJava"></a>

以下 S3 on Outposts 示例说明如何使用适用于 Java 的 SDK 从 Outposts 存储桶检索正在进行的分段上传的列表。要使用此示例，请将每个 `user input placeholder` 替换为您自己的信息。

```
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ListMultipartUploadsRequest;
import com.amazonaws.services.s3.model.MultipartUpload;
import com.amazonaws.services.s3.model.MultipartUploadListing;

import java.util.List;

public class ListMultipartUploads {
    public static void main(String[] args) {
                String accessPointArn = "*** access point ARN ***";

        try {
            // This code expects that you have Amazon credentials set up per:
            // https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/setup-credentials.html
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .enableUseArnRegion()
                    .build();

            // Retrieve a list of all in-progress multipart uploads.
            ListMultipartUploadsRequest allMultipartUploadsRequest = new ListMultipartUploadsRequest(accessPointArn);
            MultipartUploadListing multipartUploadListing = s3Client.listMultipartUploads(allMultipartUploadsRequest);
            List<MultipartUpload> uploads = multipartUploadListing.getMultipartUploads();

            // Display information about all in-progress multipart uploads.
            System.out.println(uploads.size() + " multipart upload(s) in progress.");
            for (MultipartUpload u : uploads) {
                System.out.println("Upload in progress: Key = \"" + u.getKey() + "\", id = " + u.getUploadId());
            }
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}
```