在Spring Service Layer中使用HttpServletRequest

Question

Environment :

Spring MVC 3

Angular JS

Tomcat 6

Issue :

We are migrating a legacy application from struts2 to spring MVC REST with angular JS as UI. This is a typical SPA.

The typical application flow is : Angular JS + Spring REST controller + Service layer

The business logic in struts2 actions is moved to service classes.

My question is - What is the correct way to make HttpServetRequest object available to Service classes in Spring ?

Two options available are :

1)Pass HttpServletRequest to Spring MVC controller method. Pass the same HttpServetRequest to Spring service layer. But this will result in HttpServletRequest being part of Service interface like -

public ProductDto getProductDetails(HttpServletRequest req,int productId)

Is this a correct way ? Can HttpServletRequest be part of Service interface ?

2)Use Spring provided API :

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

Please guide on this ?

Answer 1

In addition to those mentioned options, you can introduce a class or another abstraction into your service layer, then populate it with the required parts of the HttpServletRequest and use that abstraction inside the Service Layer .

For example (Borrowed from Spring Data), Suppose you want to access to page , size and sort and user related query strings from the HttpServletRequest . Instead of passing the request to the service layer methods, you can also encapsulate those parameters into an abstraction, say, Pageable or UserFilterCriteria :

public interface Pageable {
    int page();
    int size();
    List<Sort> sorts();
}

Then instead of passing the HttpServletRequest to the service layer:

public interface UsersService {
    List<User> filterUsers(HttpServletRequest request);
}

You can pass those new abstractions:

public interface UsersService {
    List<User> filterUsers(UserFilterCriteria criteria, Pageable pageable);
}

This way you can easily define abstractions in the same level of abstraction as your service layer.

Answer 2

You should rather not make HttpServletRequest/-Response be part of your service-layer, as HttpServletRequest/-Response are classes specific to your user interface/view technology. Introducing them to your service layer will make your service layer depend on the technology used for the user interface, thus making it harder to change the UI/View technology later.