mongo find()後加一個first()是什麼意思？

mongo2中只有find，findOne是mongo3中才有的，所以舊的寫法想達到和findOne一樣的效果，就需要在find後在加first()

 

In MongoDB 2 Java driver there was a method on the DBCollection class named findOne().

In the MongoDB 3 Java driver API, the findOne() method isn't there. So your new code for finding exactly one document becomes similar too this one:

collection.find(eq("_id", 3)).first()