1. The error message is shown in the figure below:

2. Solution: find .idea in the project and delete misc.xml file.

PS: why generated misc.xml file:

(1) Possible causes (take me as an example): I shut down my computer when running a web project, resulting in abnormal idea editor. All Tomcat related configurations in idea are missing.

Solution: reinstall idea

Reinstall idea details: when uninstalling tips: do not delete those history records and configurations

I. Tomcat startup error: internal error (Java. Lang. IllegalStateException): duplicate key (internal error (Java. Lang. IllegalStateException): duplicate key):

— find the .idea delete misc.xml file

II. Tomcat related configurations in idea are missing:

– reinstall idea (when uninstalling tips: do not delete those history records and configurations)