MongoDB java 查询嵌套JSON数据？

Question

如何在java中查询存在MongoDB里的嵌套json格式的数据？
这是我的json数据：
{ "_id" : ObjectId("59eac603b2921c583a1a38c1"), "mj1" : { "source" : 104963,"dj":"mih", "n
umber" : 3, "target" : 100322，"weights" : 122 }, "mj2" : { "source" : 109601,"dj":"mih", "number" : 4, "ta
rget" : 105710，"weights" : 10 } }
{ "_id" : ObjectId("59eac6b7b2921c583a1a38cd"), "mj1" : [ { "source" : 104963,"dj":"mih",
"number" : 3, "target" : 100322，"weights" : 1022 },"mj2" : { "source" : 109601,"dj":"mih", "number" : 4, "target" :
105710，"weights" : 2 } ] }
我先用了这句话（ db.mjj.find({"mjj1":{"$ne" : null,$exists : true}})）查询，可以得到如上结果，但是，我只想查询"source","number","target"，这三样，该如何编写程序？CMD的命令和JAVA的命令回答都可以。

Answer 1

db.mjj.find({"$and": [{mj1.source: 12345}, {mj1.number: 22345}, {mj1.target: 32345}]}