title: How to externalize web.xml servlet init-param? Spring DelegatingFilterProxy for Servlets?
body: <p>I have a 3rd-party servlet that I cannot modify. It accepts an <code>init-param</code> that I would like to externalize (from web.xml).</p>
  
  <p>I can externalize a servlet filter <code>init-param</code> using <a href="http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/web/filter/DelegatingFilterProxy.html" rel="noreferrer">DelegatingFilterProxy</a>. This effectively moves the servlet filter definition into Spring where there are much more powerful externalization tools (eg: PropertyPlaceholderConfigurer, environment variables, etc.)</p>
  
  <p>How can I do this for a servlet?</p>