Java Reflection mechanism Demo (iv)-Gets the parent class of a class and the implemented interface

Java Reflection mechanism Demo (iv)-Gets the parent class of a class and implements the interface 1,java reflection mechanism to get the parent class of a class

Use the Getsuperclass () method in class to get the parent class of a class

If this Class represents Object a class, an interface, a base type, or void, NULL is returned. If this object represents an array class, the object representing the Object class is returned Class .

Test code:

Package Com.aaron.reflect;public class Demo4 {public static void main (string[] args) {class<?> C = integer.class; System.out.println ("The parent class of the integer is:" +c.getsuperclass ()); c = Number.class; System.out.println ("Number's parent class is:" +c.getsuperclass ()); c = Object.class; System.out.println ("The parent class of object is:" +c.getsuperclass ());}}

Operation Result:

The parent class of the integer is: Class Java.lang.NumberNumber's parent class is: Class Java.lang.ObjectObject's parent class is: null

Because Java does not have multiple inheritance, a class can have at most one parent class, so the return type is not an array.

2,java reflection mechanism returns an interface implemented by a class

When we develop an interface and implement it with a class, we see a class that knows what interface it implements, but when the machine itself gets a class, it does not know what interface it implements. Through the reflection mechanism, you can take the class object of an interface implemented by a class, so that you can explore the structure inside the interface.

A simple demo is given in this article.

First, the interface is defined as follows;

Package Com.aaron.reflect;public interface Animal {public static final String name = "Animal";p ublic String SayHello (strin g name);}

Then, define a class to implement this interface

Package Com.aaron.reflect;import Java.util.jar.attributes.name;public class Dog implements Animal {public final static String name = "Dog"; @Overridepublic string SayHello (String str) {return String.Format ("%s  says:%s", this.name, str); }}

There is only one method in both the interface and the implementation class.

The code for the test class is as follows:

Package Com.aaron.reflect;public class Demo3 {public static void main (string[] args) {class<?> C = dog.class;//Get Dog The corresponding Class object class<?> interfaces[] = c.getinterfaces ();//Get all interfaces implemented by dog for (class<?> inte:interfaces) {// Print System.out.println ("Dog Implements Interface:" +inte);}}}

Operation Result:

Dog implementation interface: interface Com.aaron.reflect.Animal

Of course, Java does not have many inheritance, but it can implement multiple interfaces, so here an array is returned.

It is important to note that:

Class<?>[] Getinterfaces () in the array, the interface object Order and the order of the interface names in the Implements clause in the class represented by this object are consistent .

Java Reflection mechanism Demo (iv)-Gets the parent class of a class and the implemented interface