code: private static Class<?> getIdClass(Class<?> entityClass) {
          Type[] genTypes = entityClass.getGenericInterfaces();
  
          for (int i = 0; i < genTypes.length; i++) {
              Type genType = genTypes[i];
              String s1 = genType.getClass().getName();
              String s2 = BaseEntity.class.getName();
              if (s1.startsWith(s2)) {
                  Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
                  // ID真实的class
                  Class<?> mapperClass = (Class<?>) params[0];
                  return mapperClass;
              }
          }
  
          return null;
      }
docs: 获取实体的ID泛型
  @param entityClass
  @return