code: public static Table getTable(Class<?> clazz)
  			throws NoTableAnnotationException {
  		Class<?> curClass = clazz;
  		while (curClass != null) {
  			Table table = curClass.getAnnotation(Table.class);
  			if(table != null) {
  				return table;
  			}
  			curClass = curClass.getSuperclass();
  		}
  		
  		throw new NoTableAnnotationException("class " + clazz.getName()
  					+ " does not have @Table annotation.");
  	}
docs: 获取DO的@Table信息，如果子类没有，会往父类查找
  
  @param clazz
  @throws NoTableAnnotationException 当clazz没有@Table注解时抛出NoTableAnnotationException
  @return