Question

I’m using spring-data jpa 1.1.0.M1 now we were using a much higher version and run into issues with spring-data-mongodb due to spring-data-commons. Because of that we’ve used entity manager in our service for certain query including queries with offset and limit.

Now that we’ve downgraded and everything seems to be fine we would like to maintain everything under repository level when it comes to data access and do much on Business Logic in the Services.

From this documentation i understand that pageable interface is what i need. But the implementation class PageRequest takes page argument. would that mean that my offset becomes the following?

offset = page* limit; => page = offset/limit; 

Am I getting it right?
thanks for reading this.

Answer 1

The PageRequest object has a constructor that takes the page and the size. Other constructors allow you to specify additional detail such as the sort direction.

new PageRequest(int page, int size) 

See: Spring PageRequest API Documentation

The PageRequest is passed as an argument to one of your repositories find methods. In the following example I am getting the first five entries for my blog.

@RequestMapping("/")
public String blog(Model model) {
    Sort sort = new Sort(Direction.DESC, "postId");
    model.addAttribute("posts",
            postViewRepository.findAll(new PageRequest(0, 5, sort))
                    .getContent());
    model.addAttribute("tease", true);
    return "blog/blog";
}

In this example the call to the repositories findAll(PageRequest) method returns a org.springframework.data.domain.Page object. The Page object contains several convenient methods that allow information about the underlying ResultSet, such as size and number of pages, to be retrieved.

See: Spring Page API Documentation

Given these convenient features, I’m not sure you need to be concerned with managing the offset or the current page since Spring Data is performing this work for you.