Spring sending object from view to a controller

Question

How can I send an object from a View to a Controller?
I'm first using a Controller 1 to display this object on a View 1 using Thymeleaf, the object is ${object}. Then what I want to do is to click a button and send this object back to a Controller 2 so that I can display that same object from View 1 to View 2. How do you do that, can you give me an example please?

Right now I can do that using the ID of the object in the URL and then requesting the parameter in Controller 2, then getting the object based on the ID. But I don't want to see the object ID in the URL, what is another method?

Answer 1

If you don't want to use an id in the URL, then you can create a form with a hidden field and submit that to your controller.

<form th:object="${formData}" method="post">
  <input type="hidden" th:field="*{id}">
  <button type="submit">
</form>

With the controller like this:

@Controller
public class MyController {

  @GetMapping
  public String showPage(Model model) {
    model.addAttribute("formData", new MyFormData("someId"));

    return "myTemplate";
  }

  @PostMapping
  public String handleId(@ModelAttribute("formData") MyFormData formData) {
    String id = formData.getId();
    
    // do something with id here
  }
}

But it seems you make it a bit hard with this requirement. Any particular reason you don't want to show the id in the URL?