如何将“uid”为“14743423697176l”的“logout_time”字段从int32类型转换为int64类型？
目前知道$type用来转换，但具体怎么写还请大神解答！
下面是错误代码：
BasicDBObject bson = new BasicDBObject("uid", 14743423697176l);
BasicDBObject bson1 = new BasicDBObject("logout_time", 1474342369l);
BasicDBObject bson2 = new BasicDBObject("$type", bson1);
userCollection.updateOne(bson, bson2);