MongoDb3.2 group by 实现方式 java版

最近在搞mongo 一个group by搞了好久, 终于搞出来了 .贴出来帮助下需要的小伙伴.

/**
  * 
  * 多条件查询例子
  */
 public void moreQueryExmple() {
  List<Bson> list = new ArrayList<Bson>();
  Bson bson1 = Filters.eq("trans_type", "免费资源查询");
  Bson bson2 = Filters.eq("ret_code", "0");
  list.add(bson1);
  list.add(bson2);
  Bson bson = Filters.and(list);
  FindIterable<Document> ll = MongoUtil.instance.getCollection("lghtest",
    "detailList").find(bson);
 }
 /***
  * 
  * 多条件查询带group by 带order by
  */
 public void moreQueryAndGroupBy() {
  Map<String, Object> map = new HashMap<String, Object>();
  map.put("format", "%Y/%m/%d %H:%M:00");
  map.put("date", "$resp_time");
  MongoCollection<Document> documents = MongoUtil.instance.getCollection(
    "lghtest", "detailList");
  AggregateIterable<Document> ll = documents.aggregate(Arrays.asList(
    // new Document("$match", new Document("trans_type", "免费资源查询")),
    new Document("$group", new Document("_id", new Document(
      "ret_code", "$ret_code").append("trans_type",
      "$trans_type").append("resp_time",
      new Document("$dateToString", new Document(map))))
      .append("counts", new Document("$sum", 1))),
    new Document("$sort", new Document("_id.ret_code", 1))));
  for (Document document : ll) {
   System.out.println(document.toJson());
  }
 }