mongodb import and export data

mongodump：

mongodump --host=host --port=port--username=username --password=password --collection=collection --db=db --out=directory

mongorestore --host=host --port=port --username=username --collection=collection --db=ibook --dir=file.bson

Reproduced in: https: //www.jianshu.com/p/9ff340d908b4