处理Amazon S3对象 - AWS SDK for Java 2.x
上传对象分段上传对象删除对象复制对象列出对象更多例子

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处理Amazon S3对象

Amazon S3 对象表示一个文件或数据集合。每个对象都必须包含在一个存储桶中。

注意

最佳实践

我们建议您在Amazon S3存储桶上启用AbortIncompleteMultipartUpload生命周期规则。

该规则指示 Amazon S3 中止在启动后没有在指定天数内完成的分段上传。当超过设置的时间限制时，Amazon S3 将中止上传，然后删除未完成的上传数据。

有关更多信息，请参阅Amazon Simple Storage Service用户指南中的带有版本控制的存储桶的生命周期配置。

注意

这些代码片段假设你已经了解了基础知识，并使用中的设置对 SDK 设置单点登录访问信息配置了默认AWS证书。

上传对象

生成PutObjectRequest并提供存储段名称和密钥名称。然后将 S3Client 的putObject方法与RequestBody包含对象内容和对象的 a 一起使用。PutObjectRequest存储桶必须存在，否则服务将返回错误。

导入 

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Random;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
import software.amazon.awssdk.services.s3.model.S3Object;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteBucketRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
import software.amazon.awssdk.services.s3.model.CompletedPart;
import software.amazon.awssdk.services.s3.model.CreateBucketConfiguration;
import software.amazon.awssdk.services.s3.model.UploadPartRequest;
import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;
import software.amazon.awssdk.services.s3.model.HeadBucketRequest;
import software.amazon.awssdk.services.s3.model.HeadBucketResponse;

代码 

        Region region = Region.US_WEST_2;
        s3 = S3Client.builder()
                .region(region)
                .build();

        createBucket(s3, bucketName, region);

        PutObjectRequest objectRequest = PutObjectRequest.builder()
                .bucket(bucketName)
                .key(key)
                .build();

        s3.putObject(objectRequest, RequestBody.fromByteBuffer(getRandomByteBuffer(10_000)));

请参阅上的完整示例GitHub。

分段上传对象

使用 S3Client 的createMultipartUpload方法获取上传 ID。然后，使用 uploadPart 方法上传每个段。最后，使用 S3Client 的completeMultipartUploadAmazon S3方法通知合并所有上传的分段并完成上传操作。

导入 

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Random;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
import software.amazon.awssdk.services.s3.model.S3Object;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteBucketRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
import software.amazon.awssdk.services.s3.model.CompletedPart;
import software.amazon.awssdk.services.s3.model.CreateBucketConfiguration;
import software.amazon.awssdk.services.s3.model.UploadPartRequest;
import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;
import software.amazon.awssdk.services.s3.model.HeadBucketRequest;
import software.amazon.awssdk.services.s3.model.HeadBucketResponse;

代码 

        // First create a multipart upload and get the upload id
        CreateMultipartUploadRequest createMultipartUploadRequest = CreateMultipartUploadRequest.builder()
                .bucket(bucketName)
                .key(key)
                .build();

        CreateMultipartUploadResponse response = s3.createMultipartUpload(createMultipartUploadRequest);
        String uploadId = response.uploadId();
        System.out.println(uploadId);

        // Upload all the different parts of the object
        UploadPartRequest uploadPartRequest1 = UploadPartRequest.builder()
                .bucket(bucketName)
                 .key(key)
                .uploadId(uploadId)
                .partNumber(1).build();

        String etag1 = s3.uploadPart(uploadPartRequest1, RequestBody.fromByteBuffer(getRandomByteBuffer(5 * mB))).eTag();

        CompletedPart part1 = CompletedPart.builder().partNumber(1).eTag(etag1).build();

        UploadPartRequest uploadPartRequest2 = UploadPartRequest.builder().bucket(bucketName).key(key)
                .uploadId(uploadId)
                .partNumber(2).build();
        String etag2 = s3.uploadPart(uploadPartRequest2, RequestBody.fromByteBuffer(getRandomByteBuffer(3 * mB))).eTag();
        CompletedPart part2 = CompletedPart.builder().partNumber(2).eTag(etag2).build();


        // Finally call completeMultipartUpload operation to tell S3 to merge all uploaded
        // parts and finish the multipart operation.
        CompletedMultipartUpload completedMultipartUpload = CompletedMultipartUpload.builder()
                .parts(part1, part2)
                .build();

        CompleteMultipartUploadRequest completeMultipartUploadRequest =
                CompleteMultipartUploadRequest.builder()
                        .bucket(bucketName)
                        .key(key)
                        .uploadId(uploadId)
                        .multipartUpload(completedMultipartUpload)
                        .build();

        s3.completeMultipartUpload(completeMultipartUploadRequest);

请参阅上的完整示例GitHub。

删除对象

生成DeleteObjectRequest并提供存储段名称和密钥名称。使用 S3Client deleteObject 的方法，并将要删除的存储桶和对象的名称传递给它。指定的存储桶和对象键必须存在，否则服务将返回错误。

导入 

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Random;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.paginators.ListObjectsV2Iterable;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
import software.amazon.awssdk.services.s3.model.S3Object;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
import software.amazon.awssdk.services.s3.model.DeleteBucketRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
import software.amazon.awssdk.services.s3.model.CreateMultipartUploadResponse;
import software.amazon.awssdk.services.s3.model.CompletedMultipartUpload;
import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
import software.amazon.awssdk.services.s3.model.CompletedPart;
import software.amazon.awssdk.services.s3.model.CreateBucketConfiguration;
import software.amazon.awssdk.services.s3.model.UploadPartRequest;
import software.amazon.awssdk.services.s3.model.CompleteMultipartUploadRequest;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;
import software.amazon.awssdk.services.s3.model.HeadBucketRequest;
import software.amazon.awssdk.services.s3.model.HeadBucketResponse;

代码 

        DeleteObjectRequest deleteObjectRequest = DeleteObjectRequest.builder()
                .bucket(bucketName)
                .key(key)
                .build();

        s3.deleteObject(deleteObjectRequest);

请参阅上的完整示例GitHub。

复制对象

生成CopyObjectRequest并提供对象被复制到的存储桶名称、一个 URL 编码的字符串值（参见 urlencoder.encode 方法）以及该对象的密钥名称。使用 S3Client copyObject 的方法，然后传递对象。CopyObjectRequest指定的存储桶和对象键必须存在，否则服务将返回错误。

导入 

import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.CopyObjectRequest;
import software.amazon.awssdk.services.s3.model.CopyObjectResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;

代码 

    public static String copyBucketObject (S3Client s3, String fromBucket, String objectKey, String toBucket) {

        CopyObjectRequest copyReq = CopyObjectRequest.builder()
            .sourceBucket(fromBucket)
            .sourceKey(objectKey)
            .destinationBucket(toBucket)
            .destinationKey(objectKey)
            .build();

        try {
            CopyObjectResponse copyRes = s3.copyObject(copyReq);
            return copyRes.copyObjectResult().toString();

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }

请参阅上的完整示例GitHub。

列出对象

生成ListObjectsRequest并提供存储段名称。然后调用 S3Client 的listObjects方法并传递对象。ListObjectsRequest此方法返回ListObjectsResponse包含存储桶中所有对象的。您可以调用此对象的 contents 方法以获取对象的列表。您可以遍历这个列表来显示对象，如以下代码所示。

导入 

import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.ListObjectsRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.S3Object;
import java.util.List;

代码 

    public static void listBucketObjects(S3Client s3, String bucketName ) {

        try {
            ListObjectsRequest listObjects = ListObjectsRequest
                .builder()
                .bucket(bucketName)
                .build();

            ListObjectsResponse res = s3.listObjects(listObjects);
            List<S3Object> objects = res.contents();
            for (S3Object myValue : objects) {
                System.out.print("\n The name of the key is " + myValue.key());
                System.out.print("\n The object is " + calKb(myValue.size()) + " KBs");
                System.out.print("\n The owner is " + myValue.owner());
            }

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    //convert bytes to kbs.
    private static long calKb(Long val) {
        return val/1024;
    }

请参阅上的完整示例GitHub。

更多例子

本指南的代码示例部分包含更多使用 Amazon S3 对象的示例，包括如何下载对象。