MongoDB Java驱动程序3.x：如何将allowDiskUse = true传递给aggregate（）方法？

这仍然适用于3.0.3驱动程序：

    MongoClient client = new MongoClient(new ServerAddress("127.0.0.1", 27017));    DB test = client.getDB("test");    DBCollection sample = test.getCollection("sample");    List<DBObject> aggregationQuery = Arrays.<DBObject>asList( new BasicDBObject("$sort",new BasicDBObject("score",-1)), new BasicDBObject("$limit",1)    );    System.out.println(aggregationQuery);    Cursor aggregateOutput = sample.aggregate( aggregationQuery, AggregationOptions.builder()         .allowDiskUse(true)         .build()    );    while ( aggregateOutput.hasNext() ) {        DBObject doc = aggregateOutput.next();        System.out.println(doc);    }

当然，您也可以使用更新的类：

    MongoClient client = new MongoClient(new ServerAddress("192.168.2.4", 27017));    MongoDatabase db = client.getDatabase("test");    MongoCollection<document> collection = db.getCollection("sample");    AggregateIterable<document> result = collection.aggregate(Arrays.asList( new BasicDBObject("$sort", new BasicDBObject("score", -1)), new BasicDBObject("$limit", 1)    )).allowDiskUse(true);    MongoCursor<document> cursor = result.iterator();    while (cursor.hasNext()) {        document doc = cursor.next();        System.out.println(doc);    }

因此，

.aggregate()

AggregateIterable

.allowDiskuse()