/// <summary>
 /// 查找指定字段Term
 /// </summary>
 /// <param name="field"></param>
 /// <param name="text"></param>
 /// <param name="current"></param>
 /// <returns></returns>
 public TermModel FindTerm(string field, string text, bool current)
 {
     TermEnum enum2 = open.Reader.Terms();
     if (enum2.SkipTo(new Term(field, text))) {
         TermModel modle2 = null;
         while ((!current && enum2.Next() && field.Equals(enum2.Term().Field()))
             || current) {
             modle2 = new TermModel(enum2.Term(), enum2.DocFreq());
             break;
         }
         enum2.Close();
         return modle2;
     }
     return null;
 }
 /// <summary>
 /// 查找指定数目的Term
 /// </summary>
 /// <param name="num"></param>
 /// <returns></returns>
 public TermModel[] FindTerms(int num)
 {
     num++;
     TermInfoQueue queue = new TermInfoQueue(num);
     TermEnum enum2 = open.Reader.Terms();
     int count = 0;
     while (enum2.Next()) {
         string str = enum2.Term().Field();
         if ((currentField != null) && (!str.Equals(currentField))) {
             continue;
         }
         if (enum2.DocFreq() > count) {
             queue.Put(new TermModel(enum2.Term(), enum2.DocFreq()));
             if (queue.Size() < num) {
                 continue;
             }
             queue.Pop();
             count = ((TermModel)queue.Top()).Count;
         }
     }
     enum2.Close();
     TermModel[] modleArray = new TermModel[queue.Size()];
     for (int i = 0; i < modleArray.Length; i++) {
         modleArray[(modleArray.Length - i) - 1] = (TermModel)queue.Pop();
     }
     return modleArray;
 }