Custom @RequestParam type handler

Question

Simple and short question: Is there a way to create a handler for custom @RequestParam types in Spring MVC?

I know I can register custom WebArgumentResolver s but then I cannot bind these to parameters. Let me describe my use case:

Consider I have defined a Model Class Account :

public class Account {
    private int id;
    private String name;
    private String email;
}

My request handling method looks as follows:

@RequestMapping("/mycontroller")
public void test(Account account1, Account account2) { 
    //... 
}

If I make a request mydomain.com/mycontroller?account1=23&account2=12 I would like to automatically load the Account objects from the database and return an error if they dont exist.

Answer 1

Yes, you should just register a custom property editor:

@InitBinder
public void initBinder(WebDataBinder binder) {
    binder.registerCustomEditor(CustomType.class,
        new CustomTypePropertyEditor());
}

Update: Since you need to access the DAO, you need the property editor as a spring bean. Something like:

@Component
public class AccountPropertyEditor extends PropertyEditorSupport {
    @Inject
    private AccountDAO accountDao;
    @Override
    public void setAsText(String text) throws IllegalArgumentException {
        setValue(accountDao.getById(Integer.parseInt(text)));
    }

    @Override
    public String getAsText() {
        return String.valueOf(((Account) getValue()).getId());
    }
}

And then, when registering the editor, get the editor via injection rather than instantiating it.