Spring Data JDBC, part of the larger Spring Data family, makes it easy to easily implement JDBC based repositories. This module deals with enhanced support for JDBC based data access layers. It makes it easier to build Spring-powered applications that use data access technologies.
Spring Data JDBC does not try to be an ORM. It is not a competitor to JPA. Instead it is more of a construction kit for your personal ORM that you can define the way you like or need it.
This means that it does rather little out of the box. But it offers plenty of places where you can put your own logic, or integrate it with the technology of your choice for generating SQL statements.
Spring Data repositories are inspired by the repository as described in the book Domain Driven Design by Eric Evans. One consequence of this is that you should have a repository per Aggregate Root. Aggregate Root is another concept from the same book and describes an entity which controls the lifecycle of other entities which together are an Aggregate. An Aggregate is a subset of your model which is consistent between method calls to your Aggregate Root.
Spring Data JDBC tries its best to encourage modelling your domain along these ideas.