目录：

• Elasticsearch .net client NEST 5.x 使用总结
• elasticsearch_.net_client_nest2.x_到_5.x常用方法属性差异
• Elasticsearch .net client NEST使用说明 2.x -更新版
• Elasticsearch .Net Client NEST使用说明 2.x

• 2.x中仅有String类型，可设置是否分词、是否索引及分词使用的分词器。
• 5.x中拆分为Keyword类型与Text类型，Keyword 不分词，可设置是否索引；Text分词，可设置是否索引及分词使用的分词器。

          [String(Name = "Name",Index = FieldIndexOption.NotAnalyzed)]
  
          public string Name { get; set; }
  
          [String(Name = "Dic", Index = FieldIndexOption.Analyzed,Analyzer = "ik_max_word")]
  
          /// <summary>
  
          /// keyword 不分词
  
          /// </summary>
  
          [Keyword(Name = "Name", Index = true)]
  
          public string Name { get; set; }
  
          /// <summary>
  
          /// text 分词,Analyzer = "ik_max_word"
  
          /// </summary>
  
          [Text(Name = "Dic", Index = true, Analyzer = "ik_max_word")]
  
          public string Dic { get; set; }

  注：5.x已将string标记为过时特性，下个版本将移除；

  变更2 滚动扫描获取全量数据

  滚动扫描支持并行执行提高获取数据效率；

  2.x

  public void SearchScanScroll(string indexName)
  
          {
  
              string scrollid = "";
  
              var result = _client.Search<TestModel2>(s => s.Index(indexName).Query(q => q.MatchAll())
  
                  .Size()
  
                  //todo:2x中的SearchType.Scan，5.x移除
  
                  .SearchType(SearchType.Scan)
  
                  .Scroll("1m"));
  
              scrollid = result.ScrollId;
  
              int count = ;
  
              while (true)
  
              {
  
                  //得到滚动扫描的id
  
                  //执行滚动扫描得到数据 返回数据量是 result.Shards.Successful*size(查询成功的分片数*size)
  
                  var result1 = _client.Scroll<TestModel2>("1m", scrollid);
  
                  if(result1.Documents==null || !result1.Documents.Any())
  
                      break;
  
                  foreach (var info in result1.Documents)
  
                  {
  
                      count++;
  
                   Console.WriteLine(info.Id+" - "+ count);
  
                  }
  
                  //得到新的id
  
                  scrollid = result1.ScrollId;
  
              }
  
          }

  5.x

  Action<int> sc1 = (id) =>
  
              {
  
                  string scrollid = "";
  
                  //todo:5.x 多了Slice设置 移除SearchType.Scan
  
                  var result = _client.Search<TestModel5>(s => s.Index(indexName).Query(q => q.MatchAll())
  
                      .Size()
  
                      .Sort(st=>st.Descending(ds=>ds.Id))
  
                      .Scroll("1m")
  
                      //id从0开始 0,1,2...
  
                      //length=max
  
                      //例：max=3 id=0,id=1,id=2
  
                      .Slice(sl => sl.Id(id).Max())
  
                      );
  
                  //得到滚动扫描的id
  
                  scrollid = result.ScrollId;
  
                  foreach (var info in result.Documents)
  
                  {
  
                      Console.WriteLine(info.Id + " - " + " -批次count " + result.Documents.Count + " - 线程"+Thread.CurrentThread.ManagedThreadId);
  
                  }
  
                  while (true)
  
                  {
  
                      //执行滚动扫描得到数据 返回数据量是 result.Shards.Successful*size(查询成功的分片数*size)
  
                      var result1 = _client.Scroll<TestModel5>("1m", scrollid);
  
                      if (result1.Documents == null || !result1.Documents.Any())
  
                          break;
  
                      foreach (var info in result1.Documents)
  
                      {
  
                          Console.WriteLine(info.Id + " - " +" -批次count "+ result1.Documents.Count+ " - 线程" + Thread.CurrentThread.ManagedThreadId);
  
                      }
  
                      //得到新的id
  
                      scrollid = result1.ScrollId;
  
                  }
  
              };
  
             var t1= Task.Factory.StartNew(() => { sc1(); });
  
              var t2= Task.Factory.StartNew(() => { sc1(); });
  
              var t3= Task.Factory.StartNew(() => { sc1(); });
  
              t1.Wait();
  
              t2.Wait();
  
              t3.Wait();

  注：5.x 增加了Slice设置可并行拉取全量数据，移除SearchType.Scan，首次查询Search时也返回结果，2.x中设置SearchType.Scan首次Search只返回ScrollId。

  注：5.x中新增深度分页方案深度分页

  分组结果对象 Nest.KeyedBucket

  • 2.x KeyedBucket
  • 5.x KeyedBucket<object>

  聚合结果解析

  2.x

             var vendorIdGroup = (BucketAggregate)result.Aggregations["Group_Group"];
  
              foreach (var bucket1 in vendorIdGroup.Items)
  
              {
  
                  //todo:2.x KeyedBucket
  
                  var bucket = (KeyedBucket)bucket1;
  
                  var maxPrice = ((ValueAggregate)bucket.Aggregations["Dvalue_Max"]).Value;
  
              }

  5.x

              var vendorIdGroup = (BucketAggregate)result.Aggregations["Group_Group"];
  
              foreach (var bucket1 in vendorIdGroup.Items)
  
              {
  
                  //todo:5.x KeyedBucket<T>
  
                  var bucket = (KeyedBucket<object>) bucket1;
  
                  var maxPrice = ((ValueAggregate)bucket.Aggregations["Dvalue_Max"]).Value;
  
              }

  其它

  一些新的特性或接口会持续补充。