打比方一个类里边有多个内部类，怎样获取该类里边指定的某一个内部类
public class FactoryTest {

@Test
public void test2(){
    FactoryTest factoryTest = new FactoryTest();
    Class<? extends FactoryTest> clazz = factoryTest.getClass();
    Class<?>[] classes = clazz.getDeclaredClasses();
    System.out.println(Arrays.toString(classes)); //只能获取一个数组

结果：[class com.design.factory.FactoryTest$Triangle, classcom.design.factory.FactoryTest$Square, class com.design.factory.FactoryTest$Circle, interface com.design.factory.FactoryTest$Shape]
}

interface Shape{
    public abstract void draw();
}

class Circle implements Shape{
    public void draw() {
        System.out.println("draw Circle");
    }
}
class Square implements Shape{
    public void draw(){
        System.out.println("draw Square");
    }
}
class Triangle implements Shape{
    public void draw(){
        System.out.println("draw Triangle");
    }
}

}