由於公司需求，要我通過es去帥選資料，公司也沒人會，只好自己慢慢摸索，期間碰到不少坑，現在記錄下來：

1：分組查詢（比如按欄位：orderId）時報：

java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [orderid] in order to load fielddata in memory by uninverting the inverted index.

這是因為5.x+版本預設關閉了文字欄位，防止佔用過多空間，需開啟fielddata：

{
  "properties": {
    "interests": { 
      "type":     "text",
      "fielddata": true    //不建議
    }
  }

}

現在我們是用的Java操作，只需在你需要分組的欄位後面加上 .keyword 就可以了。如

.addAggregation(AggregationBuilders.terms("orderId_Term").field("orderid.keyword")

2:es預設只顯示10條記錄的問題

我們查找出的資料預設只顯示10條，要想顯示所有的呢？1·可以設定size，不靈活。2·通過scroll，即遊標。程式碼如下：

SearchResponse response = client.prepareSearch("responseqrcodes")
      .setScroll(new TimeValue(60000)).get();

也就是說在在1min內保持scroll開啟狀態，setScroll("1m")引數也可這樣寫，即1分鐘。最後獲取的時候就可以：

do {
    for (SearchHit hit : scrollResp.getHits().getHits()) {
        //Handle the hit...
    }
  response = client.prepareSearchScroll(scrollResp.getScrollId()).setScroll(new TimeValue(60000)).execute().actionGet();

} while(scrollResp.getHits().getHits().length != 0);  //所有資料讀取完畢則退出迴圈。

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下面貼一段完整程式碼：

private static void executeSearch(TransportClient client) {

        SearchResponse response = client.prepareSearch("index")
                .setScroll(new TimeValue(60000))
                .setTypes("type")
                .setQuery(QueryBuilders.matchAllQuery())
                .setPostFilter(QueryBuilders.rangeQuery("money").gt(1).lt(100)) //金額大於1小於100
//                .setQuery(QueryBuilders.matchQuery("id", "1"))  //id等於1
.addAggregation(AggregationBuilders.terms("c_term").field("country.keyword") //按國家分組
//                        .order(Terms.Order.aggregation("moneySum", false))  //按總金額降序排序 true:升序
.subAggregation(AggregationBuilders.sum("moneySum").field("money")) //對應的總金額
.subAggregation(AggregationBuilders.avg("moneyAvg").field("money")) //平均金額
)
//                .setFrom(0).setSize(20)  //分頁，20條
.addSort("id", SortOrder.ASC) //按id升序排序
.get();
Terms terms = response.getAggregations().get("c_term");
List<Terms.Bucket> buckets = terms.getBuckets();
        for (Terms.Bucket bucket : buckets) {
            Sum salarySum = bucket.getAggregations().get("moneySum");
Avg moneyAvg = bucket.getAggregations().get("moneyAvg");
System.out.println(bucket.getKey() + "----" + salarySum.getValue() + "=======" + moneyAvg.getValue());
System.out.println(bucket.getKey() + "--->" + bucket.getDocCount());
}
        SearchHits hits = response.getHits();
        long totalHits = hits.getTotalHits();
System.out.println("總數：" + totalHits);
SearchHit[] searchHits = hits.hits();
        do {
            for (SearchHit searchHit : searchHits) {
                System.out.println(searchHit.getSourceAsString());
}
            response = client.prepareSearchScroll(response.getScrollId()).setScroll(new TimeValue(60000)).execute().actionGet();
} while (response.getHits().getHits().length != 0); //零點選標記滾動結束和while迴圈。
}