Ignore properties in subclass with BeanUtils

Question

I´m usign Spring BeanUtils with this class structure

     class B{
          int b;
     }

     class A{
           int a;
           B bClass;
     }

Then receiving a instance A want to create a new one but without the value of Bb So I´m doing this:

  A a = new A();
  B b = new B();
  b.setb(2);
  a.seta(1);
  a.setbClass(b);
  A a1 = new A();
  BeanUtils.copyProperties(a, a1, new String[]{"bClass.b"});

But still the value of b attribute 2 is still coping on the a1 class.

What I´m doing wrong

Answer 1

BeanUtils.copyProperties simply copies field values. If it is a reference field it will copy it too (if it's not in ignoreProperties), it does not make deep copying. You cannot make it ignore B's fields.

Answer 2

BeanUtils.copyProperties() is intended for shallow copies, so you can't use it for nested fields. You could try with BeanWrapper , but I'm not sure there is something like ignored properties there, you might have to do it manually.