使用Java反射获取类变量

Question

I have the following class:

public final class ClassMap {

    public static final Class HELLO = HelloActivity.class;

}

I want to be able to access HelloActivity.class knowing the string "HELLO" . I've tried the following:

Field classField = ClassMap.class.getField("HELLO");

But that returns a Field object. How can I get a Class object back?

Thanks!

Answer 1

Now that you have the Field object representing the field, ask for the value, ie call classField.get(Object obj) .

Since your field is static , the obj parameter will be ignored, and you should just give a null value. Javadoc says so:

If the underlying field is a static field, the obj argument is ignored; it may be null.

So, do this:

Field classField = ClassMap.class.getField("HELLO");
Object value = classField.get(null);