何时将QueryRequest与Java SDK for AWS一起使用？

Question

We have a framework built up around QueryRequest. But our framework was built 12-18 months ago. And as I read current docs like the Developer Guide, I see no reference to QueryRequest. The example in this document ( Querying Tables Using the AWS SDK for Java Document API ) uses QuerySpec, which is completely new to me. Later in that same document there are more examples using Table.query. There is also a reference to using the Object Persistence Model.

Is QueryRequest outdated, or planned to be deprecated? Is Table.query currently the recommended method to use when you have hash keys, rangeKeyConditions, FilterExpressions, etc.?

FYI for context, we are currently building up our queryRequest with setSelect(), setTableName(), setKeyConditions(), setQueryFilter(), etc. But a new use case looks like it will need more complex combinations of AND and OR conditions, so it looks like we need to start using FilterExpressions.

Answer 1

com.amazonaws.services.dynamodbv2.model.QueryRequest is not deprecated, and it doesn't look like it is targeted to be. The com.amazonaws.services.dynamodb.model.QueryRequest (notice no v2) was deprecated and, I believe, removed in the 1.9 AWS Java SDK release.

DynamoDB released another library building on top of the low-level Java client called the Document API . AWS Developer Blog published a blog explaining its usage ( Part 1 and Part 2 ) and also mentions the reasons behind it, but it essentially makes code both easier to write and easier to read. Quoting from Part 1 :

As you see, the new Document API allows the direct use of plain old Java data types and has less boilerplate. In fact, the Dynamo Document API can be used to entirely subsume what you can do with the low level client (ie AmazonDynamoDBClient) but with a much cleaner programming model and less code.

As you can see, saving JSON as a structured document in Amazon DynamoDB , or updating, retrieving and converting the document back into JSON is as easy as 1-2-3. :) You can find more examples in the AZ Document API quick-start folder at GitHub. Happy coding until next time!

It is mostly up to how you want to write your code, but I would say that using the Document API is much easier to read and write than using the low-level Java client.