找到mongodb安装的地方,打开bin 目录，在此目录执行cmd命令，
导出单个数据集合并保存为json文件
E:\软件\mongo\bin>mongoexport.exe -d mydj -c focus -o focus.json
2019-09-05T14:21:11.384+0800 connected to: localhost
2019-09-05T14:21:11.451+0800 exported 2 records
-d:数据库名database
-c:集合名collection
-o:保存的路径，默认情况下在bin目录下,可以指定位置
导出数据库
E:\软件\mongo\bin>mongodump -d mydj -o directory
2019-09-05T15:08:29.937+0800 writing mydj.users to
2019-09-05T15:08:29.987+0800 writing mydj.summaries to
2019-09-05T15:08:29.990+0800 writing mydj.focu to
2019-09-05T15:08:29.991+0800 writing mydj.focus to
2019-09-05T15:08:30.013+0800 done dumping mydj.summaries (1 document)
2019-09-05T15:08:30.013+0800 done dumping mydj.users (2 documents)
2019-09-05T15:08:31.999+0800 done dumping mydj.focu (1 document)
2019-09-05T15:08:32.003+0800 done dumping mydj.focus (2 documents)
导入单个集合
E:\软件\mongo\bin>mongoimport --db mydj --collection focu focus.json
2019-09-05T14:42:53.629+0800 connected to: localhost
2019-09-05T14:42:53.754+0800 imported 1 document
导入多个集合（数据库）
E:\软件\mongo\bin>mongorestore.exe lala
2019-09-05T16:17:12.610+0800 preparing collections to restore from
2019-09-05T16:17:12.673+0800 reading metadata for mydj.focus from lala\mydj\focus.metadata.json
2019-09-05T16:17:12.674+0800 reading metadata for mydj.users from lala\mydj\users.metadata.json
lala是上一个导出的数据库保存的文件夹，默认保存在bin目录下，导入直接在mongorestore.exe后面加文件夹名字就行
