AWS Lambda json deserialization with jackson annotations

Question

I'm calling an aws lambda with a json body. So the fields of the json are with a different name from the ones in the POJO. So what I did is to add @JsonProperty on the fields to tell jackson what are the names in json. But for some reason, it seems that it doesn't recognize them and all the fields are null. If I pass a json with the same field names as the POJO it's working. Here's my class: 

public class Event implements Identifiable {

 

    @JsonProperty("distinct_id")

    private String distinctId;

 

    @JsonProperty("user_id")

    private Integer userId;

 

    @JsonDeserialize(using = LocalDateTimeDeserializer.class)

    @JsonSerialize(using = LocalDateTimeSerializer.class)

    private LocalDateTime eventDateTime;

 

    //Here are the getters and setters

}

If I pass 

{"distinct_id":"123", "user_id":123, "dt":"2017-01-04T08:45:04+00:00"} 

all the fields are null and with distinctId, userId, eventDateTime it's serializing ok with the exception that it also doesn't recognize my custom serializers/deserializers but this actually is the same problem.

Answer 1

To get input and output streams to work with, you need to implement RequestStreamHandler.

import com.amazonaws.services.lambda.runtime.RequestStreamHandler

 

public class ChartHandler implements RequestStreamHandler {

    private ObjectMapper objectMapper = new ObjectMapper();

 

    @Override

    public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context) throws IOException {

        DeserializationClass deserializedInput = objectMapper.readValue(inputStream, DeserializationClass.class)

        objectMapper.writeValue(outputStream, deserializedInput); //write to the outputStream what you want to return

    }

 

}

If you have the input and output streams, you can use any framework or format to parse it.