restHighLevelClient根据时间字段的年份聚合并统计数量

可以使用Elasticsearch的聚合功能来实现这个需求。具体步骤如下：

1. 创建一个SearchRequest对象，并设置索引名和查询条件。

SearchRequest searchRequest = new SearchRequest("your_index_name");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(searchSourceBuilder);

2. 添加一个按时间字段的年份进行聚合的Aggregation。

AggregationBuilder aggregation = AggregationBuilders
    .dateHistogram("year_histogram")
    .field("your_time_field_name")
    .dateHistogramInterval(DateHistogramInterval.YEAR);
searchSourceBuilder.aggregation(aggregation);

3. 执行查询，获取结果并解析。

SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
Aggregations aggregations = searchResponse.getAggregations();
Histogram yearHistogram = aggregations.get("year_histogram");
List<? extends Histogram.Bucket> buckets = yearHistogram.getBuckets();
for (Histogram.Bucket bucket : buckets) {
    String year = bucket.getKeyAsString();
    long count = bucket.getDocCount();
    System.out.println(year + ": " + count);
}

这样就可以按照时间字段的年份进行聚合并统计数量了。