There is nothing wrong with the configuration
Press the
CTRL + Alt + shift + s open Project Structure (Project Structure)
click the module without struts 2, click on the plus sign
as shown 
the user-defined structs. XML and user-defined structs - default. XML to join
Read More:
- Under idea struts.xml The problem of “red” in extends = “struts default”
- The solution of package main extensions undefined package struts default
- Struts2 is cracked, a serious loophole, a perfect solution
- In Struts2, the value read from the foreground JSP page is null
- Struts 2 encapsulates form data into list and map sets
- [Java] spring transaction control configuration error, application- persstence.xml Transaction manager report red in file
- Error report of. XML header file constraint in idea
- The solution of notes floating red error in IntelliJ idea
- Idea2020.2 encountered pom.xml The problem of file error report in Maven plug-in tomcat7
- Maven project pom.xml The solution of error report in execution of
- Idea | change the default configuration of idea to open a new project
- Solution of spring auto injection always report error in IntelliJ idea
- The solution of using Autowired annotation to report errors in IntelliJ idea
- Python Anaconda Spyder can’t display pictures by using Matplotlib. Error report solution: figures now render in the plots pane by default. To mak
- The solution of red X in eclipse error pages
- The template tags of all vscode Vue files report errors in red~
- Idea can’t find the solution of XML configuration by running project prompt through external Tomcat
- IntelliJ idea sets the default working directory
- The error of GetSet method encapsulated by idea2020 is red
- Error in pom.xml dependency version number in idea