Dispatch Action Equivalent in Spring?

[tapeshwar sharma]

Hi Craig,
I used Struts 1.2 heavily before switching over to Spring MVC since Spring 2.0.
However, I have not been able to find an equivalent yet for the DispatchAction in Struts 1.2.
Actually, not even in Struts 2.0 for that matter.
I find DispatchAction really helpful and efficient for CRUD like operations.
Does Spring 3.0 provide some Controller like that or is there an easy work around for that ?

[Anil Vupputuri]

tapeshwar sharma wrote:Hi Craig,
I used Struts 1.2 heavily before switching over to Spring MVC since Spring 2.0.
However, I have not been able to find an equivalent yet for the DispatchAction in Struts 1.2.
Actually, not even in Struts 2.0 for that matter.
I find DispatchAction really helpful and efficient for CRUD like operations.
Does Spring 3.0 provide some Controller like that or is there an easy work around for that ?

Google search yielded this link although it is for Spring 2.0

[David Newton]

Struts 2 provides dynamic method invocation.

[Craig Walls]

That link that Anil gave is in regard to Spring's MultiActionController...which is quite similar to Struts' DispatcherServlet. That's one way of doing it, I suppose. But the new Spring @MVC model lets you do the same thing without implementing/extending any special controller. For example, consider this annotated controller:

@Controller
@RequestMapping("/book")
public class BookController {
  @RequestMapping("/list")
  public void showBookList(Map<String, Object> model) {
    model.put("books", bookService.getAllBooks());
  }

  @RequestMaping(value="/{bookId}", method=RequestMethod.GET)
  public String showBookDetail(@PathParam String bookId, Map<String, Object> model) {
    model.put("book", bookService.getBookById(bookId));
    return "bookDetail";
  }

  @RequestMaping(value="/{bookId}", method=RequestMethod.DELETE)
  public String deleteBook(@PathParam String bookId) {
    bookService.deleteBook(bookId);
    return "redirect:/home";
  }

  @Autowired
  BookService bookService;
}

(Note that I wrote this controller on-the-fly...I've not actually tried it...there may be some mistakes.)

This single controller responds to 3 kinds of requests:
- Requests for "/book/list" to display a list of all books
- GET requests for "/book/{bookId}" to display details for a given book ID
- DELETE requests for "/book/{bookId}" to delete a given book

Notice the RESTful-ness of this controller. It's not exactly the same as DispatchAction or MultiActionController...but I think it's something much better.

[tapeshwar sharma]

Craig Walls wrote:That link that Anil gave is in regard to Spring's MultiActionController...which is quite similar to Struts' DispatcherServlet. That's one way of doing it, I suppose. But the new Spring @MVC model lets you do the same thing without implementing/extending any special controller. For example, consider this annotated controller:

@Controller
@RequestMapping("/book")
public class BookController {
  @RequestMapping("/list")
  public void showBookList(Map<String, Object> model) {
    model.put("books", bookService.getAllBooks());
  }

  @RequestMaping(value="/{bookId}", method=RequestMethod.GET)
  public String showBookDetail(@PathParam String bookId, Map<String, Object> model) {
    model.put("book", bookService.getBookById(bookId));
    return "bookDetail";
  }

  @RequestMaping(value="/{bookId}", method=RequestMethod.DELETE)
  public String deleteBook(@PathParam String bookId) {
    bookService.deleteBook(bookId);
    return "redirect:/home";
  }

  @Autowired
  BookService bookService;
}

(Note that I wrote this controller on-the-fly...I've not actually tried it...there may be some mistakes.)

This single controller responds to 3 kinds of requests:
- Requests for "/book/list" to display a list of all books
- GET requests for "/book/{bookId}" to display details for a given book ID
- DELETE requests for "/book/{bookId}" to delete a given book

Notice the RESTful-ness of this controller. It's not exactly the same as DispatchAction or MultiActionController...but I think it's something much better.

Hmm...this might workout . Thanks, though I am yet to explore that whether the Restful version has any side-effects.
It forces to stick to particular url format for one.But then it may not be a problem.
For the record, MultiActionController does not support the Command object. Not at least directly.
There is a Command controller but that does not support multi-operations.
This is the reason that MultiActioncontroller can not fill-in for DispatchAction without a workaround.