Question

I submit this data to add a Child entity via Ajax (POST):

(See the bottom of this question for entity classes definition)

name = "Child Name"
parent.id = 3

Everything is OK. The new Child entity is saved successfully.

But If don’t include the parent.id (only name is set) (submitted using POST method)

name = "Child Name"

The validation result return this JSON:

"errors":{"parent":"may not be null"}

Note the "parent" property in that JSON. It’s supposed to return parent.id not parent.

It causes problem as the field on client-side script (HTML) has the name "parent.id" not "parent".

Any suggestion How to return parent.id instead of parent ??

Here is the handler method:

@RequestMapping(value = "/add", method = RequestMethod.POST)
@ResponseBody
public Map<String, ?> add(@Valid Child child, BindingResult result) {

    Map<String, ?> out = new LinkedHashMap<String, ?>();

    if(result.hasErrors()){
        Map<String, String> errors = new LinkedHashMap<String, String>();
        for (FieldError error : result.getFieldErrors()) {
           errors.put(error.getField(), error.getDefaultMessage());
        }
        out.put("success", false);
        out.put("errors", errors);
        return out;
    } else {
        out.put("success", true);
    }

    return out;

}

And here are the entity classes:

class Child {
    private int id;

    @NotNull
    @Size(min = 5)
    private String name;

    @NotNull        
    private Parent parent;

    //getter and setter methods
}

class Parent {
    private int id;

    @NotNull
    private String name;

    //getter and setter methods
}

Thank you.

Answer 1

Thanks for @oehmiche for the suggestion.

I end up changing the entity classes to these:

class Child {
    @NotNull
    private int id;

    @NotNull
    @Size(min = 5)
    private String name;

    @NotNull
    @Valid
    private Parent parent = new Parent("Foo Foo");

    //getter and setter methods
}

class Parent {
    @NotNull
    private int id;

    @NotNull
    private String name;

    public Parent(){
    }

    public Parent(String name){
         setName(name);
    }

    //getter and setter methods
}

And this is the submitted data:

id = 1
name = "Child Name"
parent.id = 3

Note the id property. I end up to always set this to 1 just to bypass the @NotNull constraint. Although the id value will always be replaced by Hibernate (I use auto generation strategy).

(I add @NotNull constraint for id of Parent as well as Child class for consistency)

However, there is still one problem. I have to always set parent’s name just to bypass the validation constraint for name property of Parent:

@NotNull
@Valid
private Parent parent = new Parent("Foo Foo");

Any suggestion for this?