Solution for Cross Domain/Origin Problems with Tomcat web application and Javascripts

I believe there are a lot of people may have encountered problems when using Tomcat servlet as backend  and HTML+Javascripts(Jquery) as frontend. Most of these problems are related to the Cross-Domain security issues, especially for Chrome users. I am writing this blog to summarise my solution for this.

For example, if we host Tomcat web application at server A (192.168.1.1:8080/app) and frontend html at Apache server B (192.168.1.2)

1. Configure your existing web application with Cors Filter http://software.dzhuvinov.com/cors-filter.html(CORS Filter is the first universal solution for fitting Cross-Origin Resource Sharing (CORS) support to Java web applications. CORS is a recent W3C effort to introduce a standard mechanism for enabling cross-domain requests in web browsers and participating servers.)
2. Configure httpd.conf file in Server B add Proxypass, Proxypassreserve and ProxyPassReverseCookiePath

   ProxyRequests On
   ProxyVia On
   ProxyPass /proxy  ajp://192.168.1.1:8009/app
   ProxyPassReverse /proxy ajp://192.168.1.1:8009/app
   ProxyPassReverseCookiePath / /proxy

   The reason I use ajp(Apache JServ Protocol) and ProxyPassReverseCookiePath is that I do not want to lose any session using the ProxyPass method (each time the controller was invoked, a new session was created). If your application does not use any session control, you can just use Proxypass to normal http and without using ProxyPassReverseCookiePath

That’s all you need to do! More on the session control part you can read this blog: http://budilov.com/blog/?p=57

If you see any error in apache log such as:(13) Permission Denied, here is the solution http://wiki.apache.org/httpd/13PermissionDenied