Question

I have a web app that current uses an external directory to host static files, e.g css, velocity, in a Spring webapp. That is, the directory is inside tomcat’s webapp directory but not inside the WAR.

Other than the ability to easily edit these resources without needing to recompile-package-deploy is there any advantage to not including these files inside the war.

I seem to recall being told A LONG TIME AGO that Tomcat had poor performance in serving files static files, but I don’t have any experience that backs this up. As far as I’m aware the only advantage is that of ease of editing.

Answer 1

In general the web server in front of application server pattern is still valid:

1. web server to provide TLS/SSL termination; clients talk to your URL via HTTPS, the web server terminates SSL and forwards plain HTTP messages to your application server (tomcat). In this scenario the web server can take over the load caused by encryption (CPU utilization)
2. web server to serve static content; when it comes to high traffic sites or sites serving a large amount of static content, the web server can provide the static content. Think of an application providing a product catalog which contains high resolution images (say > 1m). Downloading images directly from the application server requires one thread on your application server. It also reduces network I/O on your application server node.
3. web server in Demilitarized Zone (DMZ); a common pattern in enterprise deployments. The web server is hosted in a zone available to the public, whereas your application server is hosted in an internal zone available to the web server only. This introduces another layer of security.
4. web server to provide static caching; web servers like Apache are doing well when it comes to caching.

No question, depending on your use case it may look different:

1. you gain most advantage of the examples provided above if your web server resides on a different server node as it’s about computing power (CPU in this case).
2. As always distributed computing introduces a layer of complexity, deployment and management in this case.
3. establishing identical security approaches on both, web server and application server may become tricky, e.g. only certain users are allowed to access certain images.

Having web server and application server on the same nodes reduces the advantages of providing a web server. My experience is that when it comes to ‘smaller’ internal applications used by ‘a few users’ a web server is not necessary and tomcat serves well. This is especially true if your app only serves some static files like icons, css and javascript.

Hope this helps…