如何通过密钥名称从mongoDB中检索值？

本文介绍了如何通过密钥名称从mongoDB中检索值？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是mongoDB的新手。我正在使用java和mongoDB。我有一个json，

I am new to mongoDB. I am using java and mongoDB. I have a json like,

[{ "_id" : { "$oid" : "4ceb753a70fdf877ef5113ca"} , "HomeTown" : "AA" , "PhoneNumber" : { "CustName" : "xxx" , "Number" : "3403290"}, "MobileNumber" : { "CustName" : "yyy" , "Number" : "9323304302"}}] [{ "_id" : { "$oid" : "4ceb753a70fdf877ef5113ca"} , "HomeTown" : "AA" , "PhoneNumber" : { "CustName" : "xxx" , "Number" : "3403290"}, "MobileNumber" : { "CustName" : "yyy" , "Number" : "9323304302"}}] [{ "_id" : { "$oid" : "4ceb753a70fdf877ef5113ca"} , "HomeTown" : "BB" , "PhoneNumber" : { "CustName" : "xxx" , "Number" : "3403290"}, "MobileNumber" : { "CustName" : "yyy" , "Number" : "9323304302"}}] [{ "_id" : { "$oid" : "4ceb753a70fdf877ef5113ca"} , "HomeTown" : "BB" , "PhoneNumber" : { "CustName" : "xxx" , "Number" : "3403290"}, "MobileNumber" : { "CustName" : "yyy" , "Number" : "9323304302"}}]

在集合中所有文档 s有不同的 HomeTown ，我只知道密钥名称 HomeTown ，我怎么能得到 HomeTown 值？

In a collection all doc's have different HomeTown, i just know the key name HomeTown, how can i get the HomeTown values?

在mongo网站中，我只能找到 find（）和 findOne（）。

In mongo site, i just can find find() and findOne().

谢谢！

推荐答案

find（ ）就足够了。

db.CollectionName.find({},{HomeTown:1})

在java中，它将是：

in java, it would be:

BasicDBObject query = new BasicDBObject(); BasicDBObject field = new BasicDBObject(); field.put("HomeTown", 1); DBCursor cursor = db.getCollection(collectionName).find(query,field); while (cursor.hasNext()) { BasicDBObject obj = (BasicDBObject) cursor.next(); result.add(obj.getString("HomeTown")); }