什么是对象的类属性指向-MyClass.class

Question

In java, what is the need/use of ".class" property of an object. eg, MyClass.class. What does .class point to.

Answer 1

An instance of the class Class .

http://javadocs.org/class

Answer 2

Sometimes you need some typing information , eg when you do some reflection .

The .class is specially handled by the compiler and is interpreted as a Class instance.

If you've used C# before this is the equivalent of the typeof operator.

eg if you want to dynamically get the full name of a type you can do:

System.out.println(String.class.getName());

Answer 3

It can be useful in some circumstances where you want to say 'any object of a particular class'. For example, in JUnit you use the class object of a class to indicate that a test is expected to throw an exception of a particular class.

They can also be useful in some advanced uses of generics, to ensure that methods are applicable only to objects of a particular type. For example, Spring HttpMessageConverter objects use them.