The phenomenon of
extends= “struts-default” when configuring struts.xml in IDEA, and also goes red when configuring interceptors with properties that don’t have pre-selection hints.
struts.xml itself is not configured incorrectly.
solution
Ctrl+Shift+Alt+S call out Project Structure
why
when we created the project, we selected the jar package that later imported struts, IDEA could not find the struts-default.xml file in the jar package. After we import the struts jar package, IDEA will not scan whether there is a struts-default.xml file in it. For IDEA, struts-default.xml is missing, so there is no corresponding code prompt for red.
This kind of problem often occurs when you manually add jar packages in struts. The solution is the same as above: manually add XML files.