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# 使用 SDK for Java 2.x 的 Kinesis 示例
<a name="java_kinesis_code_examples"></a>

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

*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。

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**
+ [操作](#actions)
+ [无服务器示例](#serverless_examples)

## 操作
<a name="actions"></a>

### `CreateStream`
<a name="kinesis_CreateStream_java_topic"></a>

以下代码示例演示了如何使用 `CreateStream`。

**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/kinesis#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.kinesis.KinesisClient;
import software.amazon.awssdk.services.kinesis.model.CreateStreamRequest;
import software.amazon.awssdk.services.kinesis.model.KinesisException;

/**
 * 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 CreateDataStream {
    public static void main(String[] args) {

        final String usage = """

                Usage:
                    <streamName>

                Where:
                    streamName - The Amazon Kinesis data stream (for example, StockTradeStream).
                """;

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

        String streamName = args[0];
        Region region = Region.US_EAST_1;
        KinesisClient kinesisClient = KinesisClient.builder()
                .region(region)
                .build();
        createStream(kinesisClient, streamName);
        System.out.println("Done");
        kinesisClient.close();
    }

    public static void createStream(KinesisClient kinesisClient, String streamName) {
        try {
            CreateStreamRequest streamReq = CreateStreamRequest.builder()
                    .streamName(streamName)
                    .shardCount(1)
                    .build();

            kinesisClient.createStream(streamReq);

        } catch (KinesisException 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[CreateStream](https://docs.aws.amazon.com/goto/SdkForJavaV2/kinesis-2013-12-02/CreateStream)*中的。

### `DeleteStream`
<a name="kinesis_DeleteStream_java_topic"></a>

以下代码示例演示了如何使用 `DeleteStream`。

**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/kinesis#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.kinesis.KinesisClient;
import software.amazon.awssdk.services.kinesis.model.DeleteStreamRequest;
import software.amazon.awssdk.services.kinesis.model.KinesisException;

/**
 * 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 DeleteDataStream {

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

                Usage:
                    <streamName>

                Where:
                    streamName - The Amazon Kinesis data stream (for example, StockTradeStream)
                """;

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

        String streamName = args[0];
        Region region = Region.US_EAST_1;
        KinesisClient kinesisClient = KinesisClient.builder()
                .region(region)
                .build();

        deleteStream(kinesisClient, streamName);
        kinesisClient.close();
        System.out.println("Done");
    }

    public static void deleteStream(KinesisClient kinesisClient, String streamName) {
        try {
            DeleteStreamRequest delStream = DeleteStreamRequest.builder()
                    .streamName(streamName)
                    .build();

            kinesisClient.deleteStream(delStream);

        } catch (KinesisException 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[DeleteStream](https://docs.aws.amazon.com/goto/SdkForJavaV2/kinesis-2013-12-02/DeleteStream)*中的。

### `GetRecords`
<a name="kinesis_GetRecords_java_topic"></a>

以下代码示例演示了如何使用 `GetRecords`。

**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/kinesis#code-examples)中查找完整示例，了解如何进行设置和运行。

```
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.kinesis.KinesisClient;
import software.amazon.awssdk.services.kinesis.model.DescribeStreamResponse;
import software.amazon.awssdk.services.kinesis.model.DescribeStreamRequest;
import software.amazon.awssdk.services.kinesis.model.Shard;
import software.amazon.awssdk.services.kinesis.model.GetShardIteratorRequest;
import software.amazon.awssdk.services.kinesis.model.GetShardIteratorResponse;
import software.amazon.awssdk.services.kinesis.model.Record;
import software.amazon.awssdk.services.kinesis.model.GetRecordsRequest;
import software.amazon.awssdk.services.kinesis.model.GetRecordsResponse;
import java.util.ArrayList;
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 GetRecords {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                    <streamName>

                Where:
                    streamName - The Amazon Kinesis data stream to read from (for example, StockTradeStream).
                """;

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

        String streamName = args[0];
        Region region = Region.US_EAST_1;
        KinesisClient kinesisClient = KinesisClient.builder()
                .region(region)
                .build();

        getStockTrades(kinesisClient, streamName);
        kinesisClient.close();
    }

    public static void getStockTrades(KinesisClient kinesisClient, String streamName) {
        String shardIterator;
        String lastShardId = null;
        DescribeStreamRequest describeStreamRequest = DescribeStreamRequest.builder()
                .streamName(streamName)
                .build();

        List<Shard> shards = new ArrayList<>();
        DescribeStreamResponse streamRes;
        do {
            streamRes = kinesisClient.describeStream(describeStreamRequest);
            shards.addAll(streamRes.streamDescription().shards());

            if (shards.size() > 0) {
                lastShardId = shards.get(shards.size() - 1).shardId();
            }
        } while (streamRes.streamDescription().hasMoreShards());

        GetShardIteratorRequest itReq = GetShardIteratorRequest.builder()
                .streamName(streamName)
                .shardIteratorType("TRIM_HORIZON")
                .shardId(lastShardId)
                .build();

        GetShardIteratorResponse shardIteratorResult = kinesisClient.getShardIterator(itReq);
        shardIterator = shardIteratorResult.shardIterator();

        // Continuously read data records from shard.
        List<Record> records;

        // Create new GetRecordsRequest with existing shardIterator.
        // Set maximum records to return to 1000.
        GetRecordsRequest recordsRequest = GetRecordsRequest.builder()
                .shardIterator(shardIterator)
                .limit(1000)
                .build();

        GetRecordsResponse result = kinesisClient.getRecords(recordsRequest);

        // Put result into record list. Result may be empty.
        records = result.records();

        // Print records
        for (Record record : records) {
            SdkBytes byteBuffer = record.data();
            System.out.printf("Seq No: %s - %s%n", record.sequenceNumber(), new String(byteBuffer.asByteArray()));
        }
    }
}
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[GetRecords](https://docs.aws.amazon.com/goto/SdkForJavaV2/kinesis-2013-12-02/GetRecords)*中的。

### `PutRecord`
<a name="kinesis_PutRecord_java_topic"></a>

以下代码示例演示了如何使用 `PutRecord`。

**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/kinesis#code-examples)中查找完整示例，了解如何进行设置和运行。

```
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.kinesis.KinesisClient;
import software.amazon.awssdk.services.kinesis.model.PutRecordRequest;
import software.amazon.awssdk.services.kinesis.model.KinesisException;
import software.amazon.awssdk.services.kinesis.model.DescribeStreamRequest;
import software.amazon.awssdk.services.kinesis.model.DescribeStreamResponse;

/**
 * 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 StockTradesWriter {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                    <streamName>

                Where:
                    streamName - The Amazon Kinesis data stream to which records are written (for example, StockTradeStream)
                """;

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

        String streamName = args[0];
        Region region = Region.US_EAST_1;
        KinesisClient kinesisClient = KinesisClient.builder()
                .region(region)
                .build();

        // Ensure that the Kinesis Stream is valid.
        validateStream(kinesisClient, streamName);
        setStockData(kinesisClient, streamName);
        kinesisClient.close();
    }

    public static void setStockData(KinesisClient kinesisClient, String streamName) {
        try {
            // Repeatedly send stock trades with a 100 milliseconds wait in between.
            StockTradeGenerator stockTradeGenerator = new StockTradeGenerator();

            // Put in 50 Records for this example.
            int index = 50;
            for (int x = 0; x < index; x++) {
                StockTrade trade = stockTradeGenerator.getRandomTrade();
                sendStockTrade(trade, kinesisClient, streamName);
                Thread.sleep(100);
            }

        } catch (KinesisException | InterruptedException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
        System.out.println("Done");
    }

    private static void sendStockTrade(StockTrade trade, KinesisClient kinesisClient,
            String streamName) {
        byte[] bytes = trade.toJsonAsBytes();

        // The bytes could be null if there is an issue with the JSON serialization by
        // the Jackson JSON library.
        if (bytes == null) {
            System.out.println("Could not get JSON bytes for stock trade");
            return;
        }

        System.out.println("Putting trade: " + trade);
        PutRecordRequest request = PutRecordRequest.builder()
                .partitionKey(trade.getTickerSymbol()) // We use the ticker symbol as the partition key, explained in
                                                       // the Supplemental Information section below.
                .streamName(streamName)
                .data(SdkBytes.fromByteArray(bytes))
                .build();

        try {
            kinesisClient.putRecord(request);
        } catch (KinesisException e) {
            System.err.println(e.getMessage());
        }
    }

    private static void validateStream(KinesisClient kinesisClient, String streamName) {
        try {
            DescribeStreamRequest describeStreamRequest = DescribeStreamRequest.builder()
                    .streamName(streamName)
                    .build();

            DescribeStreamResponse describeStreamResponse = kinesisClient.describeStream(describeStreamRequest);

            if (!describeStreamResponse.streamDescription().streamStatus().toString().equals("ACTIVE")) {
                System.err.println("Stream " + streamName + " is not active. Please wait a few moments and try again.");
                System.exit(1);
            }

        } catch (KinesisException e) {
            System.err.println("Error found while describing the stream " + streamName);
            System.err.println(e);
            System.exit(1);
        }
    }
}
```
+  有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[PutRecord](https://docs.aws.amazon.com/goto/SdkForJavaV2/kinesis-2013-12-02/PutRecord)*中的。

## 无服务器示例
<a name="serverless_examples"></a>

### 通过 Kinesis 触发器调用 Lambda 函数
<a name="serverless_Kinesis_Lambda_java_topic"></a>

以下代码示例展示了如何实现一个 Lambda 函数，该函数接收因接收来自 Kinesis 流的记录而触发的事件。该函数检索 Kinesis 有效负载，将 Base64 解码，并记录下记录内容。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在[无服务器示例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-kinesis-to-lambda)存储库中查找完整示例，并了解如何进行设置和运行。
使用 Java 将 Kinesis 事件与 Lambda 结合使用。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
package example;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.LambdaLogger;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.KinesisEvent;

public class Handler implements RequestHandler<KinesisEvent, Void> {
    @Override
    public Void handleRequest(final KinesisEvent event, final Context context) {
        LambdaLogger logger = context.getLogger();
        if (event.getRecords().isEmpty()) {
            logger.log("Empty Kinesis Event received");
            return null;
        }
        for (KinesisEvent.KinesisEventRecord record : event.getRecords()) {
            try {
                logger.log("Processed Event with EventId: "+record.getEventID());
                String data = new String(record.getKinesis().getData().array());
                logger.log("Data:"+ data);
                // TODO: Do interesting work based on the new data
            }
            catch (Exception ex) {
                logger.log("An error occurred:"+ex.getMessage());
                throw ex;
            }
        }
        logger.log("Successfully processed:"+event.getRecords().size()+" records");
        return null;
    }

}
```

### 通过 Kinesis 触发器报告 Lambda 函数批处理项目失败
<a name="serverless_Kinesis_Lambda_batch_item_failures_java_topic"></a>

以下代码示例展示了如何为接收来自 Kinesis 流的事件的 Lambda 函数实现部分批处理响应。该函数在响应中报告批处理项目失败，并指示 Lambda 稍后重试这些消息。

**适用于 Java 的 SDK 2.x**  
 还有更多相关信息 GitHub。在[无服务器示例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-kinesis-to-lambda-with-batch-item-handling)存储库中查找完整示例，并了解如何进行设置和运行。
报告使用 Java 进行 Lambda Kinesis 批处理项目失败。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.KinesisEvent;
import com.amazonaws.services.lambda.runtime.events.StreamsEventResponse;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class ProcessKinesisRecords implements RequestHandler<KinesisEvent, StreamsEventResponse> {

    @Override
    public StreamsEventResponse handleRequest(KinesisEvent input, Context context) {

        List<StreamsEventResponse.BatchItemFailure> batchItemFailures = new ArrayList<>();
        String curRecordSequenceNumber = "";

        for (KinesisEvent.KinesisEventRecord kinesisEventRecord : input.getRecords()) {
            try {
                //Process your record
                KinesisEvent.Record kinesisRecord = kinesisEventRecord.getKinesis();
                curRecordSequenceNumber = kinesisRecord.getSequenceNumber();

            } catch (Exception e) {
                /* Since we are working with streams, we can return the failed item immediately.
                   Lambda will immediately begin to retry processing from this failed item onwards. */
                batchItemFailures.add(new StreamsEventResponse.BatchItemFailure(curRecordSequenceNumber));
                return new StreamsEventResponse(batchItemFailures);
            }
        }
       
       return new StreamsEventResponse(batchItemFailures);   
    }
}
```