CODEWITHSUNDEEP
javaaws-lambdaamazon-dynamodbamazon-dynamodb-streams
Rahul
Rahul

Reputation: 583

Parse Dynamo Db Stream record to Object in Java

The items from the stream have the data type present in the stream.

I am trying to find a library similar to dynamodb-data-types, which can unwrap the dynamoDB structure to json structure for java. My lambda is in java.

Eg: I am trying to convert

{
    "prospectId": {
        "S": "kjhakh23444"
    },
    "campaignId": {
        "S": "kjhniujj123"
    }
}

to

{
    "prospectId": "kjhakh23444",
    "campaignId": "kjhniujj123"
}

Prospect.java

    @DynamoDBTable(tableName="Prospect")
public class Prospect {
    private String campaignId;
    private String prospectId;
    
    public Prospect() {
    }


    @DynamoDBHashKey(attributeName="campaignId")
    public String getCampaignId() {
        return campaignId;
    }

    public void setCampaignId(String campaignId) {
        this.campaignId = campaignId;
    }

    public String getProspectId() {
        return prospectId;
    }

    public void setProspectId(String prospectId) {
        this.prospectId = prospectId;
    }
}

I am trying below but as per the DynamoDbStreamRecord structure, below will not work out. How can I parse DynamoDbStreamRecord so that I get the Prospect Object?

String body = new Gson().toJson(dynamodbStreamRecord.getDynamodb().getNewImage());
    Prospect prospect = new Gson().fromJson(body, Prospect.class);

Please help me out.

Upvotes: 5

Views: 1564

Answers (1)

kjb
kjb

Reputation: 21

You can use

software.amazon.awssdk.enhanced.dynamodb.document.EnhancedDocument;

EnhancedDocument.fromAttributeValueMap(your-image-from-stream).toJson();

Note that you might need to convert the StreamRecord Pojo with

List<Record> convertedRecords = 
DynamodbEventTransformer.toRecordsV2(ddbEvent);

per

https://github.com/aws/aws-lambda-java-libs/blob/main/aws-lambda-java-events-sdk-transformer/README.md

There are different versions from com.amazonaws.services.lambda.runtime.events.DynamodbEvent and the newer (I assume) implementation software.amazon.awssdk.services.dynamodb.model

you'll find differences in AttributeValue and StreamRecord, with builders in the services.dynamodb.model e.g.

com.amazonaws.services.lambda.runtime.events.models.dynamodb.AttributeValue;
software.amazon.awssdk.services.dynamodb.model.AttributeValue;

Upvotes: 2

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