elastic按小时统计当天数据

要实现这样一个功能

select count(1),小时 from user where createDate=今天 group by 每小时

原本以为很简单的一个聚合很容易找到相关资料，没想到花了好几个小时

首先建一个测试的index和type，分别为ksearch_test和user，

建立mapping
http://ip:port/ksearch_test/user/_mapping  PUT

{
"user":{
"properties":{
"name":{
"type":"string",
"index":"not_analyzed" //不分词
},
"createDate":{
"type":"date",
"index":"not_analyzed"
}
}
}
}

实现聚合，按每小时统计当天数据：
http://ip:port/ksearch_test/user/_search  POST

{
"size": 0,
"aggs": {
"group_by_state": {
"date_histogram": {          //es提供的时间处理函数
"field": "createDate",     //需要聚合的字段名字
"interval": "hour",        //按小时group by
"format": "yyyy-MM-dd HH", //返回值格式化，HH大写，不然不能区分上午、下午
"min_doc_count": 0,        //为空填充0
"extended_bounds": {       //需要填充0的范围
"min": "2016-12-19 01",
"max": "2016-12-19 23"
}
}
}
},
"query": { //这就是where
"filtered": {
"filter": {
"range": {
"createDate": {
"gte": "2016-12-19T00:00:00.000",
"lt": "2016-12-20T00:00:00.000"
}
}
}
}
}
}

使用spring-data-elasticsearch在java中实现

@SuppressWarnings("deprecation")
@Test
public void group_by_day(){
String indexName = "ksearch_test3";
String typeName = "ks_user_trace";

//QueryBuilder queryBuilder = QueryBuilders.boolQuery().must(QueryBuilders.queryFilter(QueryBuilders.rangeQuery("create_time").gte("2016-11-19T01:00:00.000").lt("2016-12-19T00:00:00.000")));
QueryBuilder queryBuilder = QueryBuilders.queryFilter(QueryBuilders.rangeQuery("create_time").gte("2016-11-19T01:00:00.000").lt("2016-12-19T00:00:00.000"));

AbstractAggregationBuilder aggregation = AggregationBuilders.dateHistogram("group_by_day").field("create_time").interval(DateHistogramInterval.DAY).format("yyyy-MM-dd").minDocCount(0L).extendedBounds("2016-11-19", "2016-12-19");

SearchRequestBuilder reqBuilder = client.prepareSearch(indexName)
.setTypes(typeName)
.setQuery(queryBuilder)
.addAggregation(aggregation);

SearchResponse resp = reqBuilder.execute().actionGet();
Aggregations aggs = resp.getAggregations();
InternalHistogram agg = aggs.get("group_by_day");
List<Bucket> buckets =  (List<Bucket>) agg.getBuckets();

for(Bucket bucket:buckets){
Long docCount = bucket.getDocCount();
String date = bucket.getKeyAsString();

System.out.println(date+":"+docCount);
}
}