java如何转换MongoDB数据库字段类型？

Question

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);

Answer 1

http://www.jb51.net/article/50500.htm