code: public static Class<?>[] getActualClass(Type genericType) {
  
          if (genericType instanceof ParameterizedType) {
  
              Type[] actualTypes = ((ParameterizedType) genericType).getActualTypeArguments();
              Class<?>[] actualClasses = new Class<?>[actualTypes.length];
  
              int i = 0;
              while (i < actualTypes.length) {
                  Type actualType = actualTypes[i];
                  if (actualType instanceof Class<?>) {
                      actualClasses[i] = (Class<?>) actualType;
                  } else if (actualType instanceof GenericArrayType) {
                      Type componentType = ((GenericArrayType) actualType).getGenericComponentType();
                      actualClasses[i] = Array.newInstance((Class<?>) componentType, 0).getClass();
                  }
                  i++;
              }
  
              return actualClasses;
          }
  
          return EMPTY_CLASSES;
      }
docs: 从参数, 返回值, 基类的: Generic 类型信息获取传入的实际类信息。
  
  @param genericType - Generic 类型信息
  @return 实际类信息