Object o = new Long[0]
System.out.println( o.getClass().isArray() )
System.out.println( o.getClass().getName() )
Class ofArray = ???
Running the first 3 lines emits;
true
[Ljava.lang.Long;
How do I get ??? to be type long? I could parse the string and do a Class.forname(), but thats grotty. What's the easy way?
Just write
Class ofArray = o.getClass().getComponentType();
From the JavaDoc:
public Class<?> getComponentType()Returns the
Classrepresenting the component type of an array. If this class does not represent an array class this method returnsnull.
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Class.html#getComponentType():
public Class<?> getComponentType()Returns the
Classrepresenting the component type of an array. If this class does not represent an array class this method returns null...
@ddimitrov is the correct answer. Put into code it looks like this:
public <T> Class<T> testArray(T[] array) {
return array.getClass().getComponentType();
}
Even more generally, we can test first to see if the type represents an array, and then get its component:
Object maybeArray = ...
Class<?> clazz = maybeArray.getClass();
if (clazz.isArray()) {
System.out.printf("Array of type %s", clazz.getComponentType());
} else {
System.out.println("Not an array");
}
A specific example would be applying this method to an array for which the component type is already known:
String[] arr = {"Daniel", "Chris", "Joseph"};
arr.getClass().getComponentType(); // => java.lang.String
Pretty straightforward!
