DynamoDBMapper for java.time.LocalDateTime

Question

I'm utilizing java.time.LocalDateTime in my java application. I'm also trying to use DynamoDBMapper and via the annotation save the LocalDateTime variable. Unfortunately I get the following error:

DynamoDBMappingException: Unsupported type: class java.time.LocalDateTime

Is there a way to have this mapping without using DynamoDBMarshalling?

Answer 1

No AWS DynamoDB Java SDK can't map java.time.LocalDateTime natively without using any annotation.

To do this mapping, you have to use DynamoDBTypeConverted annotation introduced in the version 1.11.20 of the AWS Java SDK. Since this version, the annotation DynamoDBMarshalling is deprecated.

You can do that like this:

class MyClass {

    ...

    @DynamoDBTypeConverted( converter = LocalDateTimeConverter.class )
    public LocalDateTime getStartTime() {

        return startTime;
    }

    ...

    static public class LocalDateTimeConverter implements DynamoDBTypeConverter<String, LocalDateTime> {

        @Override
        public String convert( final LocalDateTime time ) {

            return time.toString();
        }

        @Override
        public LocalDateTime unconvert( final String stringValue ) {

            return LocalDateTime.parse(stringValue);
        }
    }
}

With this code, the stored dates are saved as string in the ISO-8601 format like that: 2016-10-20T16:26:47.299.

Answer 2

Despite what I said I found it simple enough to use DynamoDBMarshalling to marshal to and from a string. Here is my code snippet and an AWS reference:

class MyClass {

    ...

    @DynamoDBMarshalling(marshallerClass = LocalDateTimeConverter.class)
    public LocalDateTime getStartTime() {
        return startTime;
    }

    ...
    static public class LocalDateTimeConverter implements DynamoDBMarshaller<LocalDateTime> {

        @Override
        public String marshall(LocalDateTime time) {
            return time.toString();
        }

        @Override
        public LocalDateTime unmarshall(Class<LocalDateTime> dimensionType, String stringValue) {
            return LocalDateTime.parse(stringValue);
        }
    }
}