Error: couldn't connect to server localhost:27000, connection attempt failed: SocketException: Error connecting to localhost:27000 (127.0.0.1:27000) :: caused by :: Connection refused : code example

Example: Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed: SocketException: Error connecting to 127.0.0.1:27017 :: caused by :: Connection refused :

sudo service mongodb start