code: public static List<CommonSynonymDictionary.SynonymItem> convert(List<Term> sentence, boolean withUndefinedItem)
      {
          List<CommonSynonymDictionary.SynonymItem> synonymItemList = new ArrayList<CommonSynonymDictionary.SynonymItem>(sentence.size());
          for (Term term : sentence)
          {
              CommonSynonymDictionary.SynonymItem item = get(term.word);
              if (item == null)
              {
                  if (withUndefinedItem)
                  {
                      item = CommonSynonymDictionary.SynonymItem.createUndefined(term.word);
                      synonymItemList.add(item);
                  }
  
              }
              else
              {
                  synonymItemList.add(item);
              }
          }
  
          return synonymItemList;
      }
docs: 将分词结果转换为同义词列表
  @param sentence 句子
  @param withUndefinedItem 是否保留词典中没有的词语
  @return