spring - How does Spring (Boot) work with Pageable in controllers method argument?

Question

I'm curious to know how does Spring Boot work with Pageable in controllers methods? I add a Pageable parameter to my controller method and Spring handle it for me.

There is an example:

@GetMapping("search")
public ResponseEntity<List<ProductDTO>> searchProducts(
        @RequestParam(value = "query", required = false, defaultValue = "") String query,
        Pageable pageable) {
    Specification<Product> spec = Specification.where(null); 
    if(!StringUtils.isBlank(query)) {
        Node rootNode = new RSQLParser().parse(query);
        spec = rootNode.accept(new CustomRsqlVisitor<Product>());
    }
    Page<ProductDTO> page = service.searchProducts(spec, pageable);
    // My Additional code....
}

Now let's back to the main question: How does Spring handle Pageable? Then, how can I create the same business for myself to handle Specifications on input methods?

P.S. 1: I used rsql-parser to implement search over my products.

P.S. 2: You can find custom classes that are used to generate Specification under rsql package

标签： springspring-boot

Answer 1

You can look at PageableHandlerMethodArgumentResolver#resolveArgument which calls PageableHandlerMethodArgumentResolverSupport#getPageable

https://github.com/spring-projects/spring-data-commons/blob/main/src/main/java/org/springframework/data/web/PageableHandlerMethodArgumentResolver.java

https://github.com/spring-projects/spring-data-commons/blob/main/src/main/java/org/springframework/data/web/PageableHandlerMethodArgumentResolverSupport.java