org-netbeans-modules-web-frameworks-struts2.nbm
org-netbeans-modules-web-frameworks-struts2lib20011.nbm
1) Tools --> plugins --> --> Downloaded
Click on AddPlugins
2)Select files from your system
3) Click open
4) Install
5) Follow the wizard one validation warning may come then click continue button and then restart netbeans.
Now you can start developing Struts 2 Application in netbeans.