在流式響應/api 調用中未接收到數據

Question

我正在嘗試 ZF7B44CFFAFD5C52223D5498196C8A2E7BZ 響應我的 controller 中的特定方法，但它沒有給我任何數據。 有沒有更好的方法來實現這一點？

方法是streamService.getLocationData();

預期 output -

{uncertaintyRadiusInMeters=[64], latitude=[12.345678], longitude=[-12.345678], dateTimeCaptured=[1623431888949]}

SpringBoot Controller -

@RequestMapping(value = "/request-location", method= {RequestMethod.GET, RequestMethod.POST}, produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<StreamingResponseBody> requestLocation(@RequestParam MultiValueMap<String,String> form) {

    streamService.addDataToStream(form);
    streamService.buildShardIterator();
    StreamingResponseBody responseBody = outputStream -> streamService.getLocationData();
    return ResponseEntity.ok()
            .contentType(MediaType.valueOf(MediaType.APPLICATION_JSON_VALUE))
            .body(responseBody);

// 返回 streamService.getLocationData(); }

服務 -

public ResponseEntity getLocationData() {
    BasicAWSCredentials awsCredentials = new BasicAWSCredentials(awsAccessKey, awsSecretKey);
    AmazonKinesis kinesisClient = AmazonKinesisClient.builder()
            .withCredentials(new AWSStaticCredentialsProvider(awsCredentials))
            .withRegion(awsRegion)
            .build();

    GetRecordsRequest recordsRequest = new GetRecordsRequest();
    recordsRequest.setShardIterator(shardIterator.getShardIterator());
    recordsRequest.setLimit(1000);

    GetRecordsResult recordsResult = kinesisClient.getRecords(recordsRequest);
    while (!recordsResult.getRecords().isEmpty()) {
        recordsResult.getRecords().stream()
                .map(record -> new String(record.getData().array()))
                .forEach(System.out::println);
        recordsRequest.setShardIterator(recordsResult.getNextShardIterator());
        kinesisClient.getRecords(recordsRequest);
        try {
            Thread.sleep(1000);
        }
        catch (InterruptedException exception) {
            throw new RuntimeException(exception);
        }
    }
    return ResponseEntity.ok(recordsResult);
}

Answer 1

您為此服務使用舊的 V1 API。 亞馬遜非常推薦遷移到 V2：

適用於 Java 2.x 的 AWS SDK 是對 1.x 版代碼庫的重大改寫。 它建立在 Java 8+ 之上，並添加了幾個經常請求的功能。 其中包括對非阻塞 I/O 的支持以及在運行時插入不同的 HTTP 實現的能力。

Kinesis V2 示例有效。 要將記錄放入數據 stream，請使用此 Java 代碼：

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;
//snippet-end:[kinesis.java2.putrecord.import]

/**
 * To run this Java V2 code example, ensure that you have setup your development environment, including your credentials.
 *
 * For information, see this 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 = "\n" +
                "Usage:\n" +
                "    StockTradesWriter <streamName>\n\n" +
                "Where:\n" +
                "    streamName - The Amazon Kinesis data stream to which records are written (for example, StockTradeStream)\n\n" +
                "Example:\n" +
                "    StockTradesWriter streamName\n";

            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();
    }

        // snippet-start:[kinesis.java2.putrecord.main]
        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.toString());
        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) {
            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);
        }
        // snippet-end:[kinesis.java2.putrecord.main]
    }
}

要從數據 ZF7B44CFFAFD5C52223D5498196C8A2E7BZ 中檢索數據，請使用以下代碼：

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;
//snippet-end:[kinesis.java2.getrecord.import]

/**
 * Demonstrates how to read data from a Amazon Kinesis Data Stream. Before running this Java code example, populate a Data Stream
 * by running the StockTradesWriter example. That example populates a Data Stream that you can then use for this example.
 * Also, ensure that you have setup your development environment, including your credentials.
 *
 * For information, see this 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 = "\n" +
                "Usage:\n" +
                "    GetRecords <streamName>\n\n" +
                "Where:\n" +
                "    streamName - The Amazon Kinesis data stream to read from (for example, StockTradeStream).\n\n" +
                "Example:\n" +
                "    GetRecords streamName\n";

        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();
    }

    // snippet-start:[kinesis.java2.getrecord.main]
    public static void getStockTrades(KinesisClient kinesisClient, String streamName) {

            String shardIterator;
            String lastShardId = null;

            // Retrieve the Shards from a Stream
            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(shards.get(0).shardId())
                    .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.println(String.format("Seq No: %s - %s", record.sequenceNumber(),
                 new String(byteBuffer.asByteArray())));
             }
         }
        // snippet-end:[kinesis.java2.getrecord.main]
  }

您可以在此處找到 Kinesis 的所有 V2 示例：

https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javav2/example_code/kinesis/src/main/java/com/example/kinesis

如果您從未使用過 V2 API，那么我建議您從這里開始：

開始使用適用於 Java 2.x 的 AWS SDK