Possible Duplicate:
How to determine an object's class (in Java)?
Java determine which class an object is
I have following sample incomplete method to compare the object type of a given object
public void test(Object value) {
if (value.getClass() == Integer) {
System.out.println("This is an Integer");
}else if(value.getClass() == String){
System.out.println("This is a String");
}else if(value.getClass() == Float){
System.out.println("This is a Float");
}
}
The method can be called as:
test("Test");
test(12);
test(10.5f);
this method is not actually working, please help me to make it work
Use value instanceof YourClass
You can compare class tokens to each other, so you could use value.getClass() == Integer.class
. However, the simpler and more canonical way is to use instanceof
:
if (value instanceof Integer) {
System.out.println("This is an Integer");
} else if(value instanceof String) {
System.out.println("This is a String");
} else if(value instanceof Float) {
System.out.println("This is a Float");
}
Notes:
instanceof C
matches for subclasses of C
too. However, in this case all the classes listed are final
, so they have no subclasses. Thus instanceof
is probably fine here.as JB Nizet stated, such checks are not OO design. You may be able to solve this problem in a more OO way, e.g.
System.out.println("This is a(n) " + value.getClass().getSimpleName());
You want instanceof
:
if (value instanceof Integer)
This will be true even for subclasses, which is usually what you want, and it is also null-safe. If you really need the exact same class, you could do
if (value.getClass() == Integer.class)
or
if (Integer.class.equals(value.getClass())
Source: Stackoverflow.com