範例: SIP Servlet Proxy Servlet 類別

package com.example;
import java.io.IOException;
import javax.servlet.sip.*;
import java.servlet.ServletException;
public class ProxyServlet extends SipServlet {
  public void doInvite(SipServletRequest req) 
       throws ServletException, java.io.IOException {
     //get the Proxy
     Proxy p=req.getProxy();
     //turn on supervised mode so that all events come through us
     //The default on this is true but it is set to emphasize the function.
     p.setSupervised(true);     
     //set record route so we see the ACK, BYE, and OK
     p.setRecordRoute(true);
     //proxy on the request
     p.proxyTo(req.getRequestURI());
  }
public void doRequest(SipServletRequest req)
     throws ServletException, java.io.IOException {
   System.out.println(req.getMethod()+" Request from "+req.getFrom().getDisplayName());
   super.doRequest(req);
}
public void doResponse(SipServletResponse resp)
     throws ServletException, java.io.IOException {
   System.out.println(resp.getReasonPhrase()+" Response from "+resp.getTo().getDisplayName());
   super.doResponse(resp);
}
}

Proxy deployment descriptor
<sip-app>
    <display-name>ProxyServlet</display-name>
    <servlet>
        <servlet-name>ProxyServlet</servlet-name>
        <servlet-class>com.example.ProxyServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ProxyServlet</servlet-name>
        <pattern>
              <equal>
                <var>request.method</var>
                <value>INVITE</value>
              </equal>
        </pattern>
    </servlet-mapping>
</sip-app>