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{"_id":"37389873","Date":{"name":{"count":"7","user": "liyang",}
}
比如数据库中存的这个文档，我想取count中的值7，只取数字7，不要文档，改怎么实现呢？？
Finally, I used Jackson to convert the json string into a map, and then used map to slice it layer by layer, and finally returned a numerical value
db.xxx.findOne({"_id":"37389873"}, {"Date.name.count": 1}).Date.name.count
Operation effect
~/tmp ▶ cat mmm.js #!/usr/bin/env mongo var db = connect('test'); db.xxx.drop(); db.xxx.insert({ "_id": "37389873", "Date":{ "name":{"count":"7", "user": "liyang", } } }); print( db.xxx.findOne({"_id":"37389873"}, {"Date.name.count": 1}).Date.name.count ); ~/tmp ▶ ./mmm.js MongoDB shell version: 2.6.3 connecting to: test connecting to: test 7
http://jongo.org/Maybe this is what you are looking for
spring’s mongodb plug-in can satisfy
BasicQuery query = new BasicQuery(query,fields);
query is the query conditionfields is the field to be queried
collections.find(docQuery).projection(keys)
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Finally, I used Jackson to convert the json string into a map, and then used map to slice it layer by layer, and finally returned a numerical value
db.xxx.findOne({"_id":"37389873"}, {"Date.name.count": 1}).Date.name.countOperation effect
http://jongo.org/
Maybe this is what you are looking for
spring’s mongodb plug-in can satisfy
query is the query condition
fields is the field to be queried
collections.find(docQuery).projection(keys)