https://blog.csdn.net/jajavaja/article/details/7901140
There are many answers to this question on the Internet. It is common to change the label of filter-class to the following:
<filter-class>
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
</filter-class> According to the update of struts2.1, this place has changed.
Another method is to delete the namespace=”/” in struts.xml
As for this I don't know the reason
After trying the above two methods and various methods, it still does not solve the problem
Finally I changed the environment from myeclipse10 to myeclipse8.5, from glassfish to tomcat...
Replace the project import with a new project....
Keep dropping and not saving, restarting the server... Finally, by chance, it can run, halo!