I encountered a problem today: importing the maven project, Tomcat does not recognize the web project, and there is a problem with the project directory . At first I thought that the pom.xml was broken, but copied it to another path and it can be imported, which means that it is in the eclipse configuration file. Consider this project already an imported project.
Go to...workspace\projects\.metadata\.plugins\org.eclipse.m2e.jdt\ folder, there is a projectxxx.container file, delete it!