{"_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 condition fields is the field to be queried
collections.find(docQuery).projection(keys)
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
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)