Struts 2 - Creating a custom logging interceptor

1) Create a class that implements the Interceptor interface and implement the intercept() method

package info.icontraining.struts2;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class MyLoggingInterceptor implements Interceptor {

   public void destroy() { }

   public void init() { }

   public String intercept(ActionInvocation invocation) throws Exception {

      // pre-processing task
      String className = invocation.getAction().getClass().getName();
      long startTime = System.currentTimeMillis();  
      System.out.println("Before calling action: " + className);
  
      // invoking the next interceptor or the action
      String result = invocation.invoke();
  
      // post-processing task
      long endTime = System.currentTimeMillis();
      System.out.println("After calling action: " + className
  + " Time taken: " + (endTime - startTime) + " ms");
  
      return result;
   }
}

2) Configure the created interceptor in the struts.xml file. Make sure that this configuration appears at the top of the XML file within the <package> element

...
<package name="myPackage" extends="struts-default">

   <interceptors>
      <interceptor name="myLogger" 
         class="info.icontraining.struts2.MyLoggingInterceptor" />

      <interceptor-stack name="myStack">
         <interceptor-ref name="myLogger" />
         <interceptor-ref name="defaultStack" />
      </interceptor-stack>   
   </interceptors>

   <default-interceptor-ref name="myStack" />

   ...
</package>
...

3) Test the interceptor with any URL that invokes a Struts2 action. Check the server console for output statements from the interceptor.

http://localhost:8080/WebAppName/AnyAction.action