我正在使用mongojava驱动程序并尝试计算特定字段不为空或不存在的所有文档。这是我到目前为止所拥有的:Stringfield="myfieldname";BasicDBObjectnotNull=newBasicDBObject(field,BasicDBObject("$ne",null));Listcondition=Arrays.asList(notNull,1,0);BasicDBObjectaggregation=newBasicDBObject("$cond",condition);//boilerplatecodetolookupmydatabase/collecti

如何使用mongoDbjava异步驱动程序在插入到mongoDb集合后获取_idpackagetest;importorg.apache.commons.logging.Log;importorg.apache.commons.logging.LogFactory;importcom.allanbank.mongodb.MongoClient;importcom.allanbank.mongodb.MongoClientConfiguration;importcom.allanbank.mongodb.MongoCollection;importcom.allanbank.mongod