I restarted jenkins, but it takes more than 30 minutes at the init stage to download the plugin.
I suspect that the mirror server is responding slowly, but
https://mirror.ossplanet.net/jenkins is currently too slow,
and Index of /jenkins/ looks normal.
Since the above problem seems to be impossible to solve quickly,
I want to change the address, but how should I do it?
That indicates there is an error in your Jenkins definition. You should not download plugins during Jenkins startup or during Jenkins restart. Jenkins startup and Jenkins restart need to be fast for the benefit of your users and downloading plugins relies on external servers and slows the restart process.
If you are using a container image, then download the plugins into a container image that is derived from the standard Jenkins container, save that container image with the plugins installed, and use that container image.
There isn’t an elegant way to switch from one mirror server to another. The mirrorlist shows the available mirrors but the Jenkins mirror redirector service points you to the mirrors nearest your location.