配置 Java AWS Lambda 使用的 Objectmapper

Question

我正在尝试开发一个由来自 SQS 的事件触发的 AWS Lambda 函数。我正在使用spring-cloud-function-adapter-aws（版本 1.0.0.RELEASE），特别是SpringBootRequestHandler。但是，正在使用的 ObjectMapper 区分大小写，因此无法成功转换来自 SQS 的 Json。SQS 发布了以下 Json，尤其是我遇到了问题的Records字段。    {  "Records": [    {      "body": "Hello from SQS!",      "receiptHandle": "MessageReceiptHandle",      "md5OfBody": "7b270e59b47ff90a553787216d55d91d",      "eventSourceARN": "arn:aws:sqs:eu-west-1:123456789012:MyQueue",      "eventSource": "aws:sqs",      "awsRegion": "eu-west-1",      "messageId": "19dd0b57-b21e-4ac1-bd88-01bbb068cb78",      "attributes": {        "ApproximateFirstReceiveTimestamp": "1523232000001",        "SenderId": "123456789012",        "ApproximateReceiveCount": "1",        "SentTimestamp": "1523232000000"      },      "messageAttributes": {}    }  ]}我已经尝试过这个问题中的建议，但无济于事。在 Spring 中配置 ObjectMapper在我的 POJO 中，我还添加了以下注释，但它在 Lambda 之外也不起作用。@JsonProperty("Records")private List<SqsRecord> Records;任何帮助将非常感激。我的 Lambda 处理程序定义为：public class SqsEventHandler extends SpringBootRequestHandler<SqsEvent, String> {}POJO 定义为：public class SqsEvent {@JsonProperty("Records")private List<SqsRecord> records;@Datapublic class SqsRecord {    private String body;    private String receiptHandle;    private String md5OfBody;    private String eventSourceARN;    private String eventSource;    private String awsRegion;    private String messageId;}}我希望 ObjectMapper 能够读入示例消息中的 Json，但“记录”字段为空。

Answer 1

我们在很多 AWS 服务中都遇到了这个问题。您必须像这样定义一个新的映射器：

SQSMixin :

 private static interface SQSEventMixin {

    public static final String ATTRIBUTES = "attributes";

    public static final String AWS_REGION = "awsRegion";

    public static final String BODY = "body";

    public static final String EVENT_SOURCE = "eventSource";

    public static final String EVENT_SOURCE_ARN = "eventSourceARN";

    public static final String MD5_OF_BOBY = "md5OfBody";

    public static final String MD5_OF_MESSAGE_ATTRIBUTES = "md5OfMessageAttributes";

    public static final String MESSAGE_ID = "messageId";

    public static final String RECEIPT_HANDLE = "receiptHandle";

    @JsonProperty(value = "Records")

    public List<?> getRecords();

    static interface MessageMixin {

        @JsonProperty(ATTRIBUTES)

        public String getAttributes();

        @JsonProperty(ATTRIBUTES)

        public void setAttributes(String attributes);

        @JsonProperty(AWS_REGION)

        public String getAwsRegion();

        @JsonProperty(AWS_REGION)

        public void setAwsRegion(String awsRegion);

        @JsonProperty(BODY)

        public Object getBody();

        @JsonProperty(BODY)

        public void setBody(Object body);

        @JsonProperty(EVENT_SOURCE)

        public String getEventSource();

        @JsonProperty(EVENT_SOURCE)

        public void setEventSource(String eventSource);

        @JsonProperty(EVENT_SOURCE_ARN)

        public String getEventSourceArn();

        @JsonProperty(EVENT_SOURCE_ARN)

        public void setEventSourceArn(String eventSourceArn);

        @JsonProperty(MD5_OF_BOBY)

        public String getMd5OfBody();

        @JsonProperty(MD5_OF_BOBY)

        public void setMd5OfBody(String md5OfBody);

        @JsonProperty(MD5_OF_MESSAGE_ATTRIBUTES)

        public String getMd5OfMessageAttributes();

        @JsonProperty(MD5_OF_MESSAGE_ATTRIBUTES)

        public void setMd5OfMessageAttributes(String md5OfMessageAttributes);

        @JsonProperty(MESSAGE_ID)

        public String getMessageId();

        @JsonProperty(MESSAGE_ID)

        public void setMessageId(String messageId);

        @JsonProperty(RECEIPT_HANDLE)

        public String getReceiptHandle();

        @JsonProperty(RECEIPT_HANDLE)

        public void setReceiptHandle(String receiptHandle);

    }

}

记录策略：

private static class UpperCaseRecordsPropertyNamingStrategy extends PropertyNamingStrategy.PropertyNamingStrategyBase {

    private static final long serialVersionUID = 1L;

    @Override

    public String translate(String propertyName) {

        if (propertyName.equals("records")) {

            return "Records";

        }

        return propertyName;

    }

}

日期格式化程序：

private static final DateTimeFormatter dateTimeFormatter = ISODateTimeFormat.dateTime()

        .withZone(new FixedDateTimeZone("GMT", "GMT", 0, 0));

private static class DateTimeMapperModule extends SimpleModule {

    private static final long serialVersionUID = 1L;

    public DateTimeMapperModule() {

        super("DateTimeMapperModule");

        super.addSerializer(DateTime.class, new DateTimeSerializer());

        super.addDeserializer(DateTime.class, new DateTimeDeserializer());

    }

}

private static class DateTimeSerializer extends JsonSerializer<DateTime> {

    @Override

    public void serialize(DateTime value, JsonGenerator gen, SerializerProvider provider) throws IOException {

        gen.writeString(dateTimeFormatter.print(value));

    }

}

private static class DateTimeDeserializer extends JsonDeserializer<DateTime> {

    @Override

    public DateTime deserialize(JsonParser parser, DeserializationContext context) throws IOException {

        return dateTimeFormatter.parseDateTime(parser.getText());

    }

}

并声明您的映射器：

    ObjectMapper mapper = new ObjectMapper();

    mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);

    mapper.setPropertyNamingStrategy(new UpperCaseRecordsPropertyNamingStrategy());

    mapper.registerModule(new DateTimeMapperModule());

    mapper.addMixIn(SQSMessage.class, SQSEventMixin.MessageMixin.class);

    SQSEvent request = mapper.convertValue(inputObject, SQSEvent.class);