文档 AWS SDK 示例 GitHub 存储库中还有更多 [S AWS DK 示例](https://github.com/awsdocs/aws-doc-sdk-examples)。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# 使用 SDK for Java 2.x 的 Step Functions 示例
<a name="java_2_sfn_code_examples"></a>

以下代码示例向您展示了如何使用 with Step Functions 来执行操作和实现常见场景。 AWS SDK for Java 2.x 

*基本功能*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。

**Topics**
+ [开始使用](#get_started)
+ [基本功能](#basics)
+ [操作](#actions)
+ [场景](#scenarios)

## 开始使用
<a name="get_started"></a>

### 开始使用 Step Functions
<a name="sfn_Hello_java_2_topic"></a>

以下代码示例显示了如何开始使用 Step Functions。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。
Java 版本的 Hello。  

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sfn.SfnClient;
import software.amazon.awssdk.services.sfn.model.ListStateMachinesResponse;
import software.amazon.awssdk.services.sfn.model.SfnException;
import software.amazon.awssdk.services.sfn.model.StateMachineListItem;
import java.util.List;

/**
 * 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 ListStateMachines {
    public static void main(String[] args) {
        Region region = Region.US_EAST_1;
        SfnClient sfnClient = SfnClient.builder()
                .region(region)
                .build();

        listMachines(sfnClient);
        sfnClient.close();
    }

    public static void listMachines(SfnClient sfnClient) {
        try {
            ListStateMachinesResponse response = sfnClient.listStateMachines();
            List<StateMachineListItem> machines = response.stateMachines();
            for (StateMachineListItem machine : machines) {
                System.out.println("The name of the state machine is: " + machine.name());
                System.out.println("The ARN value is : " + machine.stateMachineArn());
            }

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[ListStateMachines](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListStateMachines)*中的。

## 基本功能
<a name="basics"></a>

### 了解基本功能
<a name="sfn_Scenario_GetStartedStateMachines_java_2_topic"></a>

以下代码示例展示了如何：
+ 创建活动。
+ 根据包含先前创建的活动作为步骤的 Amazon States Language 定义创建状态机。
+ 运行状态机并使用用户输入响应活动。
+ 运行完成后获取最终状态和输出，然后清理资源。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples) 中查找完整示例，了解如何进行设置和运行。

```
/**
 * You can obtain the JSON file to create a state machine in the following
 * GitHub location.
 * <p>
 * https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/resources/sample_files
 * <p>
 * To run this code example, place the chat_sfn_state_machine.json file into
 * your project's resources folder.
 * <p>
 * Also, set up your development environment, including your credentials.
 * <p>
 * For information, see this documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 * <p>
 * This Java code example performs the following tasks:
 * <p>
 * 1. Creates an activity.
 * 2. Creates a state machine.
 * 3. Describes the state machine.
 * 4. Starts execution of the state machine and interacts with it.
 * 5. Describes the execution.
 * 6. Delete the activity.
 * 7. Deletes the state machine.
 */
public class StepFunctionsScenario {
    public static final String DASHES = new String(new char[80]).replace("\0", "-");

    public static void main(String[] args) throws Exception {
        final String usage = """

            Usage:
                <roleARN> <activityName> <stateMachineName>

            Where:
                roleName - The name of the IAM role to create for this state machine.
                activityName - The name of an activity to create.
                stateMachineName - The name of the state machine to create.
                jsonFile - The location of the chat_sfn_state_machine.json file. You can located it in resources/sample_files. 
            """;

        if (args.length != 4) {
            System.out.println(usage);
            System.exit(1);
        }

        String roleName = args[0];
        String activityName = args[1];
        String stateMachineName = args[2];
        String jsonFile = args[3];
        String polJSON = """
            {
                "Version":"2012-10-17",		 	 	 
                "Statement": [
                    {
                        "Sid": "",
                        "Effect": "Allow",
                        "Principal": {
                            "Service": "states.amazonaws.com"
                        },
                        "Action": "sts:AssumeRole"
                    }
                ]
            }
            """;


        Scanner sc = new Scanner(System.in);
        boolean action = false;

        Region region = Region.US_EAST_1;
        SfnClient sfnClient = SfnClient.builder()
            .region(region)
            .build();

        Region regionGl = Region.AWS_GLOBAL;
        IamClient iam = IamClient.builder()
            .region(regionGl)
            .build();

        System.out.println(DASHES);
        System.out.println("Welcome to the AWS Step Functions example scenario.");
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("1. Create an activity.");
        String activityArn = createActivity(sfnClient, activityName);
        System.out.println("The ARN of the activity is " + activityArn);
        System.out.println(DASHES);

        // Read the file using FileInputStream
        FileInputStream inputStream = new FileInputStream(jsonFile);
        ObjectMapper mapper = new ObjectMapper();
        JsonNode jsonNode = mapper.readValue(inputStream, JsonNode.class);
        String jsonString = mapper.writeValueAsString(jsonNode);

        // Modify the Resource node.
        ObjectMapper objectMapper = new ObjectMapper();
        JsonNode root = objectMapper.readTree(jsonString);
        ((ObjectNode) root.path("States").path("GetInput")).put("Resource", activityArn);

        // Convert the modified Java object back to a JSON string.
        String stateDefinition = objectMapper.writeValueAsString(root);
        System.out.println(stateDefinition);

        System.out.println(DASHES);
        System.out.println("2. Create a state machine.");
        String roleARN = createIAMRole(iam, roleName, polJSON);
        String stateMachineArn = createMachine(sfnClient, roleARN, stateMachineName, stateDefinition);
        System.out.println("The ARN of the state machine is " + stateMachineArn);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("3. Describe the state machine.");
        describeStateMachine(sfnClient, stateMachineArn);
        System.out.println("What should ChatSFN call you?");
        String userName = sc.nextLine();
        System.out.println("Hello " + userName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        // The JSON to pass to the StartExecution call.
        String executionJson = "{ \"name\" : \"" + userName + "\" }";
        System.out.println(executionJson);
        System.out.println("4. Start execution of the state machine and interact with it.");
        String runArn = startWorkflow(sfnClient, stateMachineArn, executionJson);
        System.out.println("The ARN of the state machine execution is " + runArn);
        List<String> myList;
        while (!action) {
            myList = getActivityTask(sfnClient, activityArn);
            System.out.println("ChatSFN: " + myList.get(1));
            System.out.println(userName + " please specify a value.");
            String myAction = sc.nextLine();
            if (myAction.compareTo("done") == 0)
                action = true;

            System.out.println("You have selected " + myAction);
            String taskJson = "{ \"action\" : \"" + myAction + "\" }";
            System.out.println(taskJson);
            sendTaskSuccess(sfnClient, myList.get(0), taskJson);
        }
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("5. Describe the execution.");
        describeExe(sfnClient, runArn);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("6. Delete the activity.");
        deleteActivity(sfnClient, activityArn);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("7. Delete the state machines.");
        deleteMachine(sfnClient, stateMachineArn);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("The AWS Step Functions example scenario is complete.");
        System.out.println(DASHES);
    }

    public static String createIAMRole(IamClient iam, String rolename, String polJSON) {
        try {
            CreateRoleRequest request = CreateRoleRequest.builder()
                .roleName(rolename)
                .assumeRolePolicyDocument(polJSON)
                .description("Created using the AWS SDK for Java")
                .build();

            CreateRoleResponse response = iam.createRole(request);
            return response.role().arn();

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

    public static void describeExe(SfnClient sfnClient, String executionArn) {
        try {
            DescribeExecutionRequest executionRequest = DescribeExecutionRequest.builder()
                .executionArn(executionArn)
                .build();

            String status = "";
            boolean hasSucceeded = false;
            while (!hasSucceeded) {
                DescribeExecutionResponse response = sfnClient.describeExecution(executionRequest);
                status = response.statusAsString();
                if (status.compareTo("RUNNING") == 0) {
                    System.out.println("The state machine is still running, let's wait for it to finish.");
                    Thread.sleep(2000);
                } else if (status.compareTo("SUCCEEDED") == 0) {
                    System.out.println("The Step Function workflow has succeeded");
                    hasSucceeded = true;
                } else {
                    System.out.println("The Status is neither running or succeeded");
                }
            }
            System.out.println("The Status is " + status);

        } catch (SfnException | InterruptedException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

    public static void sendTaskSuccess(SfnClient sfnClient, String token, String json) {
        try {
            SendTaskSuccessRequest successRequest = SendTaskSuccessRequest.builder()
                .taskToken(token)
                .output(json)
                .build();

            sfnClient.sendTaskSuccess(successRequest);

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

    public static List<String> getActivityTask(SfnClient sfnClient, String actArn) {
        List<String> myList = new ArrayList<>();
        GetActivityTaskRequest getActivityTaskRequest = GetActivityTaskRequest.builder()
            .activityArn(actArn)
            .build();

        GetActivityTaskResponse response = sfnClient.getActivityTask(getActivityTaskRequest);
        myList.add(response.taskToken());
        myList.add(response.input());
        return myList;
    }

    public static void deleteActivity(SfnClient sfnClient, String actArn) {
        try {
            DeleteActivityRequest activityRequest = DeleteActivityRequest.builder()
                .activityArn(actArn)
                .build();

            sfnClient.deleteActivity(activityRequest);
            System.out.println("You have deleted " + actArn);

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

    public static void describeStateMachine(SfnClient sfnClient, String stateMachineArn) {
        try {
            DescribeStateMachineRequest stateMachineRequest = DescribeStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            DescribeStateMachineResponse response = sfnClient.describeStateMachine(stateMachineRequest);
            System.out.println("The name of the State machine is " + response.name());
            System.out.println("The status of the State machine is " + response.status());
            System.out.println("The ARN value of the State machine is " + response.stateMachineArn());
            System.out.println("The role ARN value is " + response.roleArn());

        } catch (SfnException e) {
            System.err.println(e.getMessage());
        }
    }

    public static void deleteMachine(SfnClient sfnClient, String stateMachineArn) {
        try {
            DeleteStateMachineRequest deleteStateMachineRequest = DeleteStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            sfnClient.deleteStateMachine(deleteStateMachineRequest);
            DescribeStateMachineRequest describeStateMachine = DescribeStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            while (true) {
                DescribeStateMachineResponse response = sfnClient.describeStateMachine(describeStateMachine);
                System.out.println("The state machine is not deleted yet. The status is " + response.status());
                Thread.sleep(3000);
            }

        } catch (SfnException | InterruptedException e) {
            System.err.println(e.getMessage());
        }
        System.out.println(stateMachineArn + " was successfully deleted.");
    }

    public static String startWorkflow(SfnClient sfnClient, String stateMachineArn, String jsonEx) {
        UUID uuid = UUID.randomUUID();
        String uuidValue = uuid.toString();
        try {
            StartExecutionRequest executionRequest = StartExecutionRequest.builder()
                .input(jsonEx)
                .stateMachineArn(stateMachineArn)
                .name(uuidValue)
                .build();

            StartExecutionResponse response = sfnClient.startExecution(executionRequest);
            return response.executionArn();

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

    public static String createMachine(SfnClient sfnClient, String roleARN, String stateMachineName, String json) {
        try {
            CreateStateMachineRequest machineRequest = CreateStateMachineRequest.builder()
                .definition(json)
                .name(stateMachineName)
                .roleArn(roleARN)
                .type(StateMachineType.STANDARD)
                .build();

            CreateStateMachineResponse response = sfnClient.createStateMachine(machineRequest);
            return response.stateMachineArn();

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

    public static String createActivity(SfnClient sfnClient, String activityName) {
        try {
            CreateActivityRequest activityRequest = CreateActivityRequest.builder()
                .name(activityName)
                .build();

            CreateActivityResponse response = sfnClient.createActivity(activityRequest);
            return response.activityArn();

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }
}
```
+ 有关 API 详细信息，请参阅《AWS SDK for Java 2.x API Reference》**中的以下主题。
  + [CreateActivity](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/CreateActivity)
  + [CreateStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/CreateStateMachine)
  + [DeleteActivity](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DeleteActivity)
  + [DeleteStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DeleteStateMachine)
  + [DescribeExecution](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DescribeExecution)
  + [DescribeStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DescribeStateMachine)
  + [GetActivityTask](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/GetActivityTask)
  + [ListActivities](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListActivities)
  + [ListStateMachines](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListStateMachines)
  + [SendTaskSuccess](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/SendTaskSuccess)
  + [StartExecution](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/StartExecution)
  + [StopExecution](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/StopExecution)

## 操作
<a name="actions"></a>

### `CreateActivity`
<a name="sfn_CreateActivity_java_2_topic"></a>

以下代码示例演示了如何使用 `CreateActivity`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static String createActivity(SfnClient sfnClient, String activityName) {
        try {
            CreateActivityRequest activityRequest = CreateActivityRequest.builder()
                .name(activityName)
                .build();

            CreateActivityResponse response = sfnClient.createActivity(activityRequest);
            return response.activityArn();

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[CreateActivity](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/CreateActivity)*中的。

### `CreateStateMachine`
<a name="sfn_CreateStateMachine_java_2_topic"></a>

以下代码示例演示了如何使用 `CreateStateMachine`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static String createMachine(SfnClient sfnClient, String roleARN, String stateMachineName, String json) {
        try {
            CreateStateMachineRequest machineRequest = CreateStateMachineRequest.builder()
                .definition(json)
                .name(stateMachineName)
                .roleArn(roleARN)
                .type(StateMachineType.STANDARD)
                .build();

            CreateStateMachineResponse response = sfnClient.createStateMachine(machineRequest);
            return response.stateMachineArn();

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[CreateStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/CreateStateMachine)*中的。

### `DeleteActivity`
<a name="sfn_DeleteActivity_java_2_topic"></a>

以下代码示例演示了如何使用 `DeleteActivity`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void deleteActivity(SfnClient sfnClient, String actArn) {
        try {
            DeleteActivityRequest activityRequest = DeleteActivityRequest.builder()
                .activityArn(actArn)
                .build();

            sfnClient.deleteActivity(activityRequest);
            System.out.println("You have deleted " + actArn);

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[DeleteActivity](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DeleteActivity)*中的。

### `DeleteStateMachine`
<a name="sfn_DeleteStateMachine_java_2_topic"></a>

以下代码示例演示了如何使用 `DeleteStateMachine`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void deleteMachine(SfnClient sfnClient, String stateMachineArn) {
        try {
            DeleteStateMachineRequest deleteStateMachineRequest = DeleteStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            sfnClient.deleteStateMachine(deleteStateMachineRequest);
            DescribeStateMachineRequest describeStateMachine = DescribeStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            while (true) {
                DescribeStateMachineResponse response = sfnClient.describeStateMachine(describeStateMachine);
                System.out.println("The state machine is not deleted yet. The status is " + response.status());
                Thread.sleep(3000);
            }

        } catch (SfnException | InterruptedException e) {
            System.err.println(e.getMessage());
        }
        System.out.println(stateMachineArn + " was successfully deleted.");
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[DeleteStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DeleteStateMachine)*中的。

### `DescribeExecution`
<a name="sfn_DescribeExecution_java_2_topic"></a>

以下代码示例演示了如何使用 `DescribeExecution`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void describeExe(SfnClient sfnClient, String executionArn) {
        try {
            DescribeExecutionRequest executionRequest = DescribeExecutionRequest.builder()
                .executionArn(executionArn)
                .build();

            String status = "";
            boolean hasSucceeded = false;
            while (!hasSucceeded) {
                DescribeExecutionResponse response = sfnClient.describeExecution(executionRequest);
                status = response.statusAsString();
                if (status.compareTo("RUNNING") == 0) {
                    System.out.println("The state machine is still running, let's wait for it to finish.");
                    Thread.sleep(2000);
                } else if (status.compareTo("SUCCEEDED") == 0) {
                    System.out.println("The Step Function workflow has succeeded");
                    hasSucceeded = true;
                } else {
                    System.out.println("The Status is neither running or succeeded");
                }
            }
            System.out.println("The Status is " + status);

        } catch (SfnException | InterruptedException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[DescribeExecution](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DescribeExecution)*中的。

### `DescribeStateMachine`
<a name="sfn_DescribeStateMachine_java_2_topic"></a>

以下代码示例演示了如何使用 `DescribeStateMachine`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void describeStateMachine(SfnClient sfnClient, String stateMachineArn) {
        try {
            DescribeStateMachineRequest stateMachineRequest = DescribeStateMachineRequest.builder()
                .stateMachineArn(stateMachineArn)
                .build();

            DescribeStateMachineResponse response = sfnClient.describeStateMachine(stateMachineRequest);
            System.out.println("The name of the State machine is " + response.name());
            System.out.println("The status of the State machine is " + response.status());
            System.out.println("The ARN value of the State machine is " + response.stateMachineArn());
            System.out.println("The role ARN value is " + response.roleArn());

        } catch (SfnException e) {
            System.err.println(e.getMessage());
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[DescribeStateMachine](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/DescribeStateMachine)*中的。

### `GetActivityTask`
<a name="sfn_GetActivityTask_java_2_topic"></a>

以下代码示例演示了如何使用 `GetActivityTask`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static List<String> getActivityTask(SfnClient sfnClient, String actArn) {
        List<String> myList = new ArrayList<>();
        GetActivityTaskRequest getActivityTaskRequest = GetActivityTaskRequest.builder()
            .activityArn(actArn)
            .build();

        GetActivityTaskResponse response = sfnClient.getActivityTask(getActivityTaskRequest);
        myList.add(response.taskToken());
        myList.add(response.input());
        return myList;
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[GetActivityTask](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/GetActivityTask)*中的。

### `ListActivities`
<a name="sfn_ListActivities_java_2_topic"></a>

以下代码示例演示了如何使用 `ListActivities`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sfn.SfnClient;
import software.amazon.awssdk.services.sfn.model.ListActivitiesRequest;
import software.amazon.awssdk.services.sfn.model.ListActivitiesResponse;
import software.amazon.awssdk.services.sfn.model.SfnException;
import software.amazon.awssdk.services.sfn.model.ActivityListItem;
import java.util.List;

/**
 * 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 ListActivities {
    public static void main(String[] args) {
        Region region = Region.US_EAST_1;
        SfnClient sfnClient = SfnClient.builder()
                .region(region)
                .build();

        listAllActivites(sfnClient);
        sfnClient.close();
    }

    public static void listAllActivites(SfnClient sfnClient) {
        try {
            ListActivitiesRequest activitiesRequest = ListActivitiesRequest.builder()
                    .maxResults(10)
                    .build();

            ListActivitiesResponse response = sfnClient.listActivities(activitiesRequest);
            List<ActivityListItem> items = response.activities();
            for (ActivityListItem item : items) {
                System.out.println("The activity ARN is " + item.activityArn());
                System.out.println("The activity name is " + item.name());
            }

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[ListActivities](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListActivities)*中的。

### `ListExecutions`
<a name="sfn_ListExecutions_java_2_topic"></a>

以下代码示例演示了如何使用 `ListExecutions`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void getExeHistory(SfnClient sfnClient, String exeARN) {
        try {
            GetExecutionHistoryRequest historyRequest = GetExecutionHistoryRequest.builder()
                    .executionArn(exeARN)
                    .maxResults(10)
                    .build();

            GetExecutionHistoryResponse historyResponse = sfnClient.getExecutionHistory(historyRequest);
            List<HistoryEvent> events = historyResponse.events();
            for (HistoryEvent event : events) {
                System.out.println("The event type is " + event.type().toString());
            }

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[ListExecutions](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListExecutions)*中的。

### `ListStateMachines`
<a name="sfn_ListStateMachines_java_2_topic"></a>

以下代码示例演示了如何使用 `ListStateMachines`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sfn.SfnClient;
import software.amazon.awssdk.services.sfn.model.ListStateMachinesResponse;
import software.amazon.awssdk.services.sfn.model.SfnException;
import software.amazon.awssdk.services.sfn.model.StateMachineListItem;
import java.util.List;

/**
 * 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 ListStateMachines {
    public static void main(String[] args) {
        Region region = Region.US_EAST_1;
        SfnClient sfnClient = SfnClient.builder()
                .region(region)
                .build();

        listMachines(sfnClient);
        sfnClient.close();
    }

    public static void listMachines(SfnClient sfnClient) {
        try {
            ListStateMachinesResponse response = sfnClient.listStateMachines();
            List<StateMachineListItem> machines = response.stateMachines();
            for (StateMachineListItem machine : machines) {
                System.out.println("The name of the state machine is: " + machine.name());
                System.out.println("The ARN value is : " + machine.stateMachineArn());
            }

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[ListStateMachines](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/ListStateMachines)*中的。

### `SendTaskSuccess`
<a name="sfn_SendTaskSuccess_java_2_topic"></a>

以下代码示例演示了如何使用 `SendTaskSuccess`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static void sendTaskSuccess(SfnClient sfnClient, String token, String json) {
        try {
            SendTaskSuccessRequest successRequest = SendTaskSuccessRequest.builder()
                .taskToken(token)
                .output(json)
                .build();

            sfnClient.sendTaskSuccess(successRequest);

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[SendTaskSuccess](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/SendTaskSuccess)*中的。

### `StartExecution`
<a name="sfn_StartExecution_java_2_topic"></a>

以下代码示例演示了如何使用 `StartExecution`。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/stepfunctions#code-examples)中查找完整示例，了解如何进行设置和运行。

```
    public static String startWorkflow(SfnClient sfnClient, String stateMachineArn, String jsonEx) {
        UUID uuid = UUID.randomUUID();
        String uuidValue = uuid.toString();
        try {
            StartExecutionRequest executionRequest = StartExecutionRequest.builder()
                .input(jsonEx)
                .stateMachineArn(stateMachineArn)
                .name(uuidValue)
                .build();

            StartExecutionResponse response = sfnClient.startExecution(executionRequest);
            return response.executionArn();

        } catch (SfnException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[StartExecution](https://docs.aws.amazon.com/goto/SdkForJavaV2/states-2016-11-23/StartExecution)*中的。

## 场景
<a name="scenarios"></a>

### 使用 Step Functions 调用 Lambda 函数
<a name="cross_ServerlessWorkflows_java_2_topic"></a>

以下代码示例显示如何创建按顺序调用 AWS Lambda 函数的 AWS Step Functions 状态机。

**适用于 Java 的 SDK 2.x**  
 演示如何使用 AWS Step Functions 和创建 AWS 无服务器工作流程。 AWS SDK for Java 2.x每个工作流程步骤都是使用 AWS Lambda 函数实现的。  
 有关如何设置和运行的完整源代码和说明，请参阅上的完整示例[GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/usecases/creating_workflows_stepfunctions)。  

**本示例中使用的服务**
+ DynamoDB
+ Lambda
+ Amazon SES
+ Step Functions