Issue with Caching and dynamo db combination

问题:

I am using AWS Elasticache and here is the method I am using with annotation,

@Cacheable(unless = "#result != null and #result.size() == 0")
public List<SomeObject> findById(String id) {
    return dynamoDBMapper.query(SomeObject.class, queryExpression(id));
}

Here is my query expression,

DynamoDBQueryExpression<SomeObject> queryExpression(String id) {
    SomeObject object = new SomeObject();
    object.setId(id);
    return new DynamoDBQueryExpression<SomeObject>()
            .withIndexName("idIndex")
            .withConsistentRead(false)
            .withHashKeyValues(object)
            .withLimit(Integer.MAX_VALUE);
}

I keep on getting this error in my application log,

java.io.NotSerializableException: com.amazonaws.services.dynamodbv2.datamodeling.PaginatedQueryList

Looks like it needs the PaginatedQueryList class as Serializable. Though I am trying to cache List, not sure how this PaginatedQueryList is coming into the picture.

Appreciate help!

回答1:

PaginatedQueryList is the concrete List implementation returned by Dynamodb's query method. You'll have to copy your results into a serializable implementation of List, like ArrayList.