搭HeadObject配 AWS SDK 或命令列工具使用 - Amazon Simple Storage Service

本文為英文版的機器翻譯版本,如內容有任何歧義或不一致之處,概以英文版為準。

HeadObject配 AWS SDK 或命令列工具使用

下列程式碼範例會示範如何使用HeadObject

CLI
AWS CLI

下列命令會擷取值區中名為之物件的中繼資料my-bucket

aws s3api head-object --bucket my-bucket --key index.html

輸出:

{ "AcceptRanges": "bytes", "ContentType": "text/html", "LastModified": "Thu, 16 Apr 2015 18:19:14 GMT", "ContentLength": 77, "VersionId": "null", "ETag": "\"30a6ec7e1a9ad79c203d05a589c8b400\"", "Metadata": {} }
  • 如需 API 詳細資訊,請參閱AWS CLI 命令參考HeadObject中的。

Java
適用於 Java 2.x 的 SDK
注意

還有更多關於 GitHub。尋找完整範例,並了解如何在AWS 設定和執行程式碼範例儲存庫

判斷物件的內容類型。

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.HeadObjectRequest; import software.amazon.awssdk.services.s3.model.HeadObjectResponse; import software.amazon.awssdk.services.s3.model.S3Exception; /** * Before running this Java V2 code example, set up your development * environment, including your credentials. * * For more information, see the following documentation topic: * * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html */ public class GetObjectContentType { public static void main(String[] args) { final String usage = """ Usage: <bucketName> <keyName>> Where: bucketName - The Amazon S3 bucket name.\s keyName - The key name.\s """; if (args.length != 2) { System.out.println(usage); System.exit(1); } String bucketName = args[0]; String keyName = args[1]; Region region = Region.US_EAST_1; S3Client s3 = S3Client.builder() .region(region) .build(); getContentType(s3, bucketName, keyName); s3.close(); } public static void getContentType(S3Client s3, String bucketName, String keyName) { try { HeadObjectRequest objectRequest = HeadObjectRequest.builder() .key(keyName) .bucket(bucketName) .build(); HeadObjectResponse objectHead = s3.headObject(objectRequest); String type = objectHead.contentType(); System.out.println("The object content type is " + type); } catch (S3Exception e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } }

取得物件的還原狀態。

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.HeadObjectRequest; import software.amazon.awssdk.services.s3.model.HeadObjectResponse; import software.amazon.awssdk.services.s3.model.S3Exception; public class GetObjectRestoreStatus { public static void main(String[] args) { final String usage = """ Usage: <bucketName> <keyName>\s Where: bucketName - The Amazon S3 bucket name.\s keyName - A key name that represents the object.\s """; if (args.length != 2) { System.out.println(usage); System.exit(1); } String bucketName = args[0]; String keyName = args[1]; Region region = Region.US_EAST_1; S3Client s3 = S3Client.builder() .region(region) .build(); checkStatus(s3, bucketName, keyName); s3.close(); } public static void checkStatus(S3Client s3, String bucketName, String keyName) { try { HeadObjectRequest headObjectRequest = HeadObjectRequest.builder() .bucket(bucketName) .key(keyName) .build(); HeadObjectResponse response = s3.headObject(headObjectRequest); System.out.println("The Amazon S3 object restoration status is " + response.restore()); } catch (S3Exception e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } }
  • 如需 API 詳細資訊,請參閱 AWS SDK for Java 2.x API 參考HeadObject中的。

Ruby
適用於 Ruby 的開發套件
注意

還有更多關於 GitHub。尋找完整範例,並了解如何在AWS 設定和執行程式碼範例儲存庫

require "aws-sdk-s3" # Wraps Amazon S3 object actions. class ObjectExistsWrapper attr_reader :object # @param object [Aws::S3::Object] An Amazon S3 object. def initialize(object) @object = object end # Checks whether the object exists. # # @return [Boolean] True if the object exists; otherwise false. def exists? @object.exists? rescue Aws::Errors::ServiceError => e puts "Couldn't check existence of object #{@object.bucket.name}:#{@object.key}. Here's why: #{e.message}" false end end # Example usage: def run_demo bucket_name = "doc-example-bucket" object_key = "my-object.txt" wrapper = ObjectExistsWrapper.new(Aws::S3::Object.new(bucket_name, object_key)) exists = wrapper.exists? puts "Object #{object_key} #{exists ? 'does' : 'does not'} exist." end run_demo if $PROGRAM_NAME == __FILE__
  • 如需 API 詳細資訊,請參閱 AWS SDK for Ruby API 參考HeadObject中的。

如需 AWS SDK 開發人員指南和程式碼範例的完整清單,請參閱透過 AWS SDK 使用此服務。此主題也包含有關入門的資訊和舊版 SDK 的詳細資訊。