code: public static String[] getXhash(String groupName, String unitName) {
          try {
              return UnitRouter.SINGLETON.newestDefinition(Unit.fullName(groupName, unitName)).getInput().getXhashNames();
          } catch (UnitUndefinedException e) {
              throw new RuntimeException("Please call UnitJudge.defined() first.", e);
          }
      }
docs: 注意：请先使用{{@link #defined(String, String)}}检查合法性，然后再使用本方法取属性