导入方式
mongoimport --db "dbName" --collection "collName" --type json --file "fileName.json" --jsonArray
json的数据格式为：
[
{ name: "Name1", msg: "This is msg 1" },
{ name: "Name2", msg: "This is msg 2" },
{ name: "Name3", msg: "This is msg 3" }
]
