Why will the contents of the file be cleared after docker restart?

  docker, question

The first is:
A container was started using mirroring.
I modified something in the container.
After docker restart < Container id >, there is nothing modified in the container.

The second is:
The mapped file was modified on the host computer, and the modifications on the host computer disappeared after the restart.

The third is:
After modifying the contents of the container, after using the docker commit, rerun the mirror image after the Commit, and the contents of the mirror image do not exist.

Docker beginner, who is the great god to help analyze the above three situations?

I’m sorry, DockerNoneEmpty or restore some added or modified data.

Please check the startup command and the entry command of the container to see if there is any operation to empty or restore the added or modified contents.