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。
AWS SDK for Java 提供三個具有 Amazon EMR 功能的套件：
如需有關這些套件的詳細資訊，請參閱 AWS SDK for Java API 參考。
以下範例說明 SDK 如何利用 Amazon EMR 簡化程式設計。下方程式碼範例使用 StepFactory 物件 (用來建立一般 Amazon EMR 步驟類型的協助程式類別) 來建立已啟用偵錯功能的互動式 Hive 叢集。
import com.amazonaws.AmazonClientException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.elasticmapreduce.AmazonElasticMapReduce;
import com.amazonaws.services.elasticmapreduce.AmazonElasticMapReduceClientBuilder;
import com.amazonaws.services.elasticmapreduce.model.*;
import com.amazonaws.services.elasticmapreduce.util.StepFactory;
public class Main {
public static void main(String[] args) {
AWSCredentialsProvider profile = null;
try {
credentials_profile = new ProfileCredentialsProvider("default"); // specifies any named profile in
// .aws/credentials as the credentials provider
} catch (Exception e) {
throw new AmazonClientException(
"Cannot load credentials from .aws/credentials file. " +
"Make sure that the credentials file exists and that the profile name is defined within it.",
e);
}
// create an EMR client using the credentials and region specified in order to
// create the cluster
AmazonElasticMapReduce emr = AmazonElasticMapReduceClientBuilder.standard()
.withCredentials(credentials_profile)
.withRegion(Regions.US_WEST_1)
.build();
// create a step to enable debugging in the AWS Management Console
StepFactory stepFactory = new StepFactory();
StepConfig enabledebugging = new StepConfig()
.withName("Enable debugging")
.withActionOnFailure("TERMINATE_JOB_FLOW")
.withHadoopJarStep(stepFactory.newEnableDebuggingStep());
// specify applications to be installed and configured when EMR creates the
// cluster
Application hive = new Application().withName("Hive");
Application spark = new Application().withName("Spark");
Application ganglia = new Application().withName("Ganglia");
Application zeppelin = new Application().withName("Zeppelin");
// create the cluster
RunJobFlowRequest request = new RunJobFlowRequest()
.withName("MyClusterCreatedFromJava")
.withReleaseLabel("emr-5.20.0") // specifies the EMR release version label, we recommend the latest release
.withSteps(enabledebugging)
.withApplications(hive, spark, ganglia, zeppelin)
.withLogUri("s3://path/to/my/emr/logs") // a URI in S3 for log files is required when debugging is enabled
.withServiceRole("EMR_DefaultRole") // replace the default with a custom IAM service role if one is used
.withJobFlowRole("EMR_EC2_DefaultRole") // replace the default with a custom EMR role for the EC2 instance
// profile if one is used
.withInstances(new JobFlowInstancesConfig()
.withEc2SubnetId("subnet-12ab34c56")
.withEc2KeyName("myEc2Key")
.withInstanceCount(3)
.withKeepJobFlowAliveWhenNoSteps(true)
.withMasterInstanceType("m4.large")
.withSlaveInstanceType("m4.large"));
RunJobFlowResult result = emr.runJobFlow(request);
System.out.println("The cluster ID is " + result.toString());
}
}
至少，您必須通過分別對應至 EMR_DefaultRole 和 EMR_EC2_DefaultRole 的服務角色和 jobflow 角色。您可以針對相同帳戶叫用此 AWS CLI 命令來執行此操作。首先，檢視該角色是否已存在：
aws iam list-roles | grep EMR若執行個體描述檔 (EMR_EC2_DefaultRole) 和服務角色 (EMR_DefaultRole) 皆存在，它們都將顯示於：
"RoleName": "EMR_DefaultRole", "Arn": "arn:aws:iam::AccountID:role/EMR_DefaultRole" "RoleName": "EMR_EC2_DefaultRole", "Arn": "arn:aws:iam::AccountID:role/EMR_EC2_DefaultRole"
如果預設的角色不存在，您可以使用以下命令以建立它們：
aws emr create-default-roles