@InitBinder in spring boot not working with @RequestBody

Question

If I use @InitBinder without limiting it,it is working fine with @RequestBody to validate my objects.

@InitBinder
private void initBinder(WebDataBinder binder) {
    binder.setValidator(validator);
}



@RequestMapping(method=RequestMethod.POST)
public CustomerQuickRegisterEntity saveNewCustomer(@Valid @RequestBody  CustomerQuickRegisterEntity customerEntity,BindingResult result)
{
    if(result.hasErrors())
    {
        return new CustomerQuickRegisterEntity();
    }
    return customerQuickRegisterRepository.save(customerEntity);

}

But problem is that when i limit it to just one object by doing it as @InitBinder("customerEntity") it is not validating the object. So I have searched through stackoverflow and found that @InitBinding only works with objects annotated with @ModelAttribute. Then my question is that it is working fine with @RequestBody when I use it as @InitBinder but does not work well when I use it as @InitBinder("customerEntity") ...why is it so? Is there any other way to validate Objects(Not properties of object Individually) associated with @RequestBody

Answer 1

This is an old question, but I've managed to get the @InitBinder annotation to bind my custom Validator to a @Valid @RequestBody parameter like this:

@InitBinder
private void bindMyCustomValidator(WebDataBinder binder) {
    if ("entityList".equals(binder.getObjectName())) {
        binder.addValidators(new MyCustomValidator());
    }
}

If you try to filter the bound argument by setting the value of the annotation, then it won't work for a @RequestBody argument. So here I check the object name instead. My method parameter is actually called entities, but Spring had decided to call it entityList. I had to debug it to discover this.

Answer 2

From the docs,

Default is to apply to all command/form attributes and all request parameters processed by the annotated handler class. Specifying model attribute names or request parameter names here restricts the init-binder method to those specific attributes/parameters, with different init-binder methods typically applying to different groups of attributes or parameters.

Please have a look here