elasticsearch 查询排序 调用 SearchSourceBuilder.sort方法
sort(String name, SortOrder order)

name:字段名

SortOrder：SortOrder.DESC 倒序，SortOrder.ASC 正序

代码如下：

SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
SortBuilder sortBuilder = SortBuilders.fieldSort("sn").order(SortOrder.DESC);
searchSourceBuilder.sort("createDate", SortOrder.DESC );