使用 SDK for Kotlin 的 Amazon S3 示例 - AWS SDK 代码示例
基本功能操作场景

AWS 文档 SDK 示例 GitHub 存储库中还有更多 AWS SDK 示例。

使用 SDK for Kotlin 的 Amazon S3 示例

以下代码示例演示如何通过将 AWS SDK for Kotlin 与 Amazon S3 结合使用，来执行操作和实现常见场景。

基础知识是向您展示如何在服务中执行基本操作的代码示例。

操作是大型程序的代码摘录，必须在上下文中运行。您可以通过操作了解如何调用单个服务函数，还可以通过函数相关场景的上下文查看操作。

场景是向您演示如何通过在一个服务中调用多个函数或与其他 AWS 服务 结合来完成特定任务的代码示例。

每个示例都包含一个指向完整源代码的链接，您可以从中找到有关如何在上下文中设置和运行代码的说明。

基本功能

以下代码示例展示了如何：

  • 创建桶并将文件上载到其中。

  • 从桶中下载对象。

  • 将对象复制到存储桶中的子文件夹。

  • 列出存储桶中的对象。

  • 删除存储桶及其对象。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun main(args: Array<String>) {
    val usage = """
    Usage:
        <bucketName> <key> <objectPath> <savePath> <toBucket>

    Where:
        bucketName - The Amazon S3 bucket to create.
        key - The key to use.
        objectPath - The path where the file is located (for example, C:/AWS/book2.pdf).   
        savePath - The path where the file is saved after it's downloaded (for example, C:/AWS/book2.pdf).     
        toBucket - An Amazon S3 bucket to where an object is copied to (for example, C:/AWS/book2.pdf). 
        """

    if (args.size != 4) {
        println(usage)
        exitProcess(1)
    }

    val bucketName = args[0]
    val key = args[1]
    val objectPath = args[2]
    val savePath = args[3]
    val toBucket = args[4]

    // Create an Amazon S3 bucket.
    createBucket(bucketName)

    // Update a local file to the Amazon S3 bucket.
    putObject(bucketName, key, objectPath)

    // Download the object to another local file.
    getObjectFromMrap(bucketName, key, savePath)

    // List all objects located in the Amazon S3 bucket.
    listBucketObs(bucketName)

    // Copy the object to another Amazon S3 bucket
    copyBucketOb(bucketName, key, toBucket)

    // Delete the object from the Amazon S3 bucket.
    deleteBucketObs(bucketName, key)

    // Delete the Amazon S3 bucket.
    deleteBucket(bucketName)
    println("All Amazon S3 operations were successfully performed")
}

suspend fun createBucket(bucketName: String) {
    val request =
        CreateBucketRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.createBucket(request)
        println("$bucketName is ready")
    }
}

suspend fun putObject(
    bucketName: String,
    objectKey: String,
    objectPath: String,
) {
    val metadataVal = mutableMapOf<String, String>()
    metadataVal["myVal"] = "test"

    val request =
        PutObjectRequest {
            bucket = bucketName
            key = objectKey
            metadata = metadataVal
            this.body = Paths.get(objectPath).asByteStream()
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        val response = s3.putObject(request)
        println("Tag information is ${response.eTag}")
    }
}

suspend fun getObjectFromMrap(
    bucketName: String,
    keyName: String,
    path: String,
) {
    val request =
        GetObjectRequest {
            key = keyName
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.getObject(request) { resp ->
            val myFile = File(path)
            resp.body?.writeToFile(myFile)
            println("Successfully read $keyName from $bucketName")
        }
    }
}

suspend fun listBucketObs(bucketName: String) {
    val request =
        ListObjectsRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->

        val response = s3.listObjects(request)
        response.contents?.forEach { myObject ->
            println("The name of the key is ${myObject.key}")
            println("The owner is ${myObject.owner}")
        }
    }
}

suspend fun copyBucketOb(
    fromBucket: String,
    objectKey: String,
    toBucket: String,
) {
    var encodedUrl = ""
    try {
        encodedUrl = URLEncoder.encode("$fromBucket/$objectKey", StandardCharsets.UTF_8.toString())
    } catch (e: UnsupportedEncodingException) {
        println("URL could not be encoded: " + e.message)
    }

    val request =
        CopyObjectRequest {
            copySource = encodedUrl
            bucket = toBucket
            key = objectKey
        }
    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.copyObject(request)
    }
}

suspend fun deleteBucketObs(
    bucketName: String,
    objectName: String,
) {
    val objectId =
        ObjectIdentifier {
            key = objectName
        }

    val delOb =
        Delete {
            objects = listOf(objectId)
        }

    val request =
        DeleteObjectsRequest {
            bucket = bucketName
            delete = delOb
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.deleteObjects(request)
        println("$objectName was deleted from $bucketName")
    }
}

suspend fun deleteBucket(bucketName: String?) {
    val request =
        DeleteBucketRequest {
            bucket = bucketName
        }
    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.deleteBucket(request)
        println("The $bucketName was successfully deleted!")
    }
}

操作

以下代码示例演示如何使用 CopyObject。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun copyBucketObject(
    fromBucket: String,
    objectKey: String,
    toBucket: String,
) {
    var encodedUrl = ""
    try {
        encodedUrl = URLEncoder.encode("$fromBucket/$objectKey", StandardCharsets.UTF_8.toString())
    } catch (e: UnsupportedEncodingException) {
        println("URL could not be encoded: " + e.message)
    }

    val request =
        CopyObjectRequest {
            copySource = encodedUrl
            bucket = toBucket
            key = objectKey
        }
    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.copyObject(request)
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 CopyObject。

以下代码示例演示如何使用 CreateBucket。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun createNewBucket(bucketName: String) {
    val request =
        CreateBucketRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.createBucket(request)
        println("$bucketName is ready")
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 CreateBucket。

以下代码示例演示如何使用 CreateMultiRegionAccessPoint。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

将 S3 控制客户端配置为向 us-west-2 区域发送请求。

        suspend fun createS3ControlClient(): S3ControlClient {
            // Configure your S3ControlClient to send requests to US West (Oregon).
            val s3Control = S3ControlClient.fromEnvironment {
                region = "us-west-2"
            }
            return s3Control
        }

创建多区域接入点。

    suspend fun createMrap(
        s3Control: S3ControlClient,
        accountIdParam: String,
        bucketName1: String,
        bucketName2: String,
        mrapName: String,
    ): String {
        println("Creating MRAP ...")
        val createMrapResponse: CreateMultiRegionAccessPointResponse =
            s3Control.createMultiRegionAccessPoint {
                accountId = accountIdParam
                clientToken = UUID.randomUUID().toString()
                details {
                    name = mrapName
                    regions = listOf(
                        Region {
                            bucket = bucketName1
                        },
                        Region {
                            bucket = bucketName2
                        },
                    )
                }
            }
        val requestToken: String? = createMrapResponse.requestTokenArn

        // Use the request token to check for the status of the CreateMultiRegionAccessPoint operation.
        if (requestToken != null) {
            waitForSucceededStatus(s3Control, requestToken, accountIdParam)
            println("MRAP created")
        }

        val getMrapResponse =
            s3Control.getMultiRegionAccessPoint(
                input = GetMultiRegionAccessPointRequest {
                    accountId = accountIdParam
                    name = mrapName
                },
            )
        val mrapAlias = getMrapResponse.accessPoint?.alias
        return "arn:aws:s3::$accountIdParam:accesspoint/$mrapAlias"
    }

等待多区域接入点变为可用状态。

        suspend fun waitForSucceededStatus(
            s3Control: S3ControlClient,
            requestToken: String,
            accountIdParam: String,
            timeBetweenChecks: Duration = 1.minutes,
        ) {
            var describeResponse: DescribeMultiRegionAccessPointOperationResponse
            describeResponse = s3Control.describeMultiRegionAccessPointOperation(
                input = DescribeMultiRegionAccessPointOperationRequest {
                    accountId = accountIdParam
                    requestTokenArn = requestToken
                },
            )

            var status: String? = describeResponse.asyncOperation?.requestStatus
            while (status != "SUCCEEDED") {
                delay(timeBetweenChecks)
                describeResponse = s3Control.describeMultiRegionAccessPointOperation(
                    input = DescribeMultiRegionAccessPointOperationRequest {
                        accountId = accountIdParam
                        requestTokenArn = requestToken
                    },
                )
                status = describeResponse.asyncOperation?.requestStatus
                println(status)
            }
        }

以下代码示例演示如何使用 DeleteBucketPolicy。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun deleteS3BucketPolicy(bucketName: String?) {
    val request =
        DeleteBucketPolicyRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.deleteBucketPolicy(request)
        println("Done!")
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 DeleteBucketPolicy。

以下代码示例演示如何使用 DeleteObjects。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun deleteBucketObjects(
    bucketName: String,
    objectName: String,
) {
    val objectId =
        ObjectIdentifier {
            key = objectName
        }

    val delOb =
        Delete {
            objects = listOf(objectId)
        }

    val request =
        DeleteObjectsRequest {
            bucket = bucketName
            delete = delOb
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.deleteObjects(request)
        println("$objectName was deleted from $bucketName")
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 DeleteObjects。

以下代码示例演示如何使用 GetBucketPolicy。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun getPolicy(bucketName: String): String? {
    println("Getting policy for bucket $bucketName")

    val request =
        GetBucketPolicyRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        val policyRes = s3.getBucketPolicy(request)
        return policyRes.policy
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 GetBucketPolicy。

以下代码示例演示如何使用 GetObject。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun getObjectBytes(
    bucketName: String,
    keyName: String,
    path: String,
) {
    val request =
        GetObjectRequest {
            key = keyName
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.getObject(request) { resp ->
            val myFile = File(path)
            resp.body?.writeToFile(myFile)
            println("Successfully read $keyName from $bucketName")
        }
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 GetObject。

以下代码示例演示如何使用 GetObjectAcl。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun getBucketACL(
    objectKey: String,
    bucketName: String,
) {
    val request =
        GetObjectAclRequest {
            bucket = bucketName
            key = objectKey
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        val response = s3.getObjectAcl(request)
        response.grants?.forEach { grant ->
            println("Grant permission is ${grant.permission}")
        }
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 GetObjectAcl。

以下代码示例演示如何使用 ListObjectsV2。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun listBucketObjects(bucketName: String) {
    val request =
        ListObjectsRequest {
            bucket = bucketName
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        val response = s3.listObjects(request)
        response.contents?.forEach { myObject ->
            println("The name of the key is ${myObject.key}")
            println("The object is ${myObject.size?.let { calKb(it) }} KBs")
            println("The owner is ${myObject.owner}")
        }
    }
}

private fun calKb(intValue: Long): Long = intValue / 1024

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 ListObjectsV2。

以下代码示例演示如何使用 PutBucketAcl。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun setBucketAcl(
    bucketName: String,
    idVal: String,
) {
    val myGrant =
        Grantee {
            id = idVal
            type = Type.CanonicalUser
        }

    val ownerGrant =
        Grant {
            grantee = myGrant
            permission = Permission.FullControl
        }

    val grantList = mutableListOf<Grant>()
    grantList.add(ownerGrant)

    val ownerOb =
        Owner {
            id = idVal
        }

    val acl =
        AccessControlPolicy {
            owner = ownerOb
            grants = grantList
        }

    val request =
        PutBucketAclRequest {
            bucket = bucketName
            accessControlPolicy = acl
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        s3.putBucketAcl(request)
        println("An ACL was successfully set on $bucketName")
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 PutBucketAcl。

以下代码示例演示如何使用 PutObject。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

suspend fun putS3Object(
    bucketName: String,
    objectKey: String,
    objectPath: String,
) {
    val metadataVal = mutableMapOf<String, String>()
    metadataVal["myVal"] = "test"

    val request =
        PutObjectRequest {
            bucket = bucketName
            key = objectKey
            metadata = metadataVal
            body = File(objectPath).asByteStream()
        }

    S3Client.fromEnvironment { region = "us-east-1" }.use { s3 ->
        val response = s3.putObject(request)
        println("Tag information is ${response.eTag}")
    }
}

  • 有关 API 详细信息，请参阅《AWS SDK for Kotlin API 参考》中的 PutObject。

场景

以下代码示例演示了如何为 Amazon S3 创建预签名 URL 以及如何上传对象。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

创建 GetObject 预签名请求并使用 URL 下载对象。

suspend fun getObjectPresigned(
    s3: S3Client,
    bucketName: String,
    keyName: String,
): String {
    // Create a GetObjectRequest.
    val unsignedRequest =
        GetObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the GetObject request.
    val presignedRequest = s3.presignGetObject(unsignedRequest, 24.hours)

    // Use the URL from the presigned HttpRequest in a subsequent HTTP GET request to retrieve the object.
    val objectContents = URL(presignedRequest.url.toString()).readText()

    return objectContents
}

使用高级选项创建 GetObject 预签名请求。

suspend fun getObjectPresignedMoreOptions(
    s3: S3Client,
    bucketName: String,
    keyName: String,
): HttpRequest {
    // Create a GetObjectRequest.
    val unsignedRequest =
        GetObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the GetObject request.
    val presignedRequest =
        s3.presignGetObject(unsignedRequest, signer = CrtAwsSigner) {
            signingDate = Instant.now() + 12.hours // Presigned request can be used 12 hours from now.
            algorithm = AwsSigningAlgorithm.SIGV4_ASYMMETRIC
            signatureType = AwsSignatureType.HTTP_REQUEST_VIA_QUERY_PARAMS
            expiresAfter = 8.hours // Presigned request expires 8 hours later.
        }
    return presignedRequest
}

创建 PutObject 预签名请求并使用它上传对象。

suspend fun putObjectPresigned(
    s3: S3Client,
    bucketName: String,
    keyName: String,
    content: String,
) {
    // Create a PutObjectRequest.
    val unsignedRequest =
        PutObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the request.
    val presignedRequest = s3.presignPutObject(unsignedRequest, 24.hours)

    // Use the URL and any headers from the presigned HttpRequest in a subsequent HTTP PUT request to retrieve the object.
    // Create a PUT request using the OKHttpClient API.
    val putRequest =
        Request
            .Builder()
            .url(presignedRequest.url.toString())
            .apply {
                presignedRequest.headers.forEach { key, values ->
                    header(key, values.joinToString(", "))
                }
            }.put(content.toRequestBody())
            .build()

    val response = OkHttpClient().newCall(putRequest).execute()
    assert(response.isSuccessful)
}

以下代码示例演示如何创建无服务器应用程序，让用户能够使用标签管理照片。

适用于 Kotlin 的 SDK

演示如何开发照片资产管理应用程序，该应用程序使用 Amazon Rekognition 检测图像中的标签并将其存储以供日后检索。

有关完整的源代码以及如何设置和运行的说明，请参阅 GitHub 上的完整示例。

要深入了解这个例子的起源，请参阅 AWS 社区上的博文。

本示例中使用的服务

  • API Gateway

  • DynamoDB

  • Lambda

  • Amazon Rekognition

  • Amazon S3

  • Amazon SNS

以下代码示例演示如何构建采用 Amazon Rekognition 来按类别检测图像中物体的应用程序。

适用于 Kotlin 的 SDK

展示如何使用 Amazon Rekognition Kotlin API 创建应用程序，该应用程序采用 Amazon Rekognition 来按类别识别位于 Amazon Simple Storage Service (Amazon S3) 存储桶的图像当中的对象。该应用程序使用 Amazon Simple Email Service (Amazon SES) 向管理员发送包含结果的电子邮件通知。

有关完整的源代码以及如何设置和运行的说明，请参阅 GitHub 上的完整示例。

本示例中使用的服务

  • Amazon Rekognition

  • Amazon S3

  • Amazon SES

以下代码示例显示如何从多区域接入点中获取对象。

适用于 Kotlin 的 SDK
注意

查看 GitHub，了解更多信息。在 AWS 代码示例存储库中查找完整示例，了解如何进行设置和运行。

将 S3 客户端配置为使用非对称 Sigv4（Sigv4a）签名算法。

        suspend fun createS3Client(): S3Client {
            // Configure your S3Client to use the Asymmetric SigV4 (SigV4a) signing algorithm.
            val sigV4aScheme = SigV4AsymmetricAuthScheme(DefaultAwsSigner)
            val s3 = S3Client.fromEnvironment {
                authSchemes = listOf(sigV4aScheme)
            }
            return s3
        }

使用多区域接入点 ARN 而不是桶名称来检索对象。

    suspend fun getObjectFromMrap(
        s3: S3Client,
        mrapArn: String,
        keyName: String,
    ): String? {
        val request = GetObjectRequest {
            bucket = mrapArn // Use the ARN instead of the bucket name for object operations.
            key = keyName
        }

        var stringObj: String? = null
        s3.getObject(request) { resp ->
            stringObj = resp.body?.decodeToString()
            if (stringObj != null) {
                println("Successfully read $keyName from $mrapArn")
            }
        }
        return stringObj
    }