how to implement the intercepters in struts2

                        

                                             Sample Example


package com.googleforjava.interceptor;

import java.util.Iterator;
import java.util.Map;


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

public class TestActionInterceptor implements Interceptor {

/**
 * 
 */
private static final long serialVersionUID = 1L;

public void destroy() {
System.out.println("CustomInterceptor destroy() is called...");

}

public void init() {
System.out.println("CustomInterceptor init() is called...");

}

public String intercept(ActionInvocation actionInvocation) throws Exception {
    System.out.println("CustomInterceptor, before invocation.invoke()...");

    Map params = actionInvocation.getInvocationContext().getParameters();
// Getting all request parameters from jsp page on which you have called any
// action
    System.out.println(params.size());
    Iterator itr = params.entrySet().iterator();
while(itr.hasNext()) {
    Object element = itr.next(); 
    System.out.print(element + " ");
    Map.Entry pairs = (Map.Entry)itr.next();
System.out.println(pairs.getKey() + " = " + pairs.getValue());
} 
System.out.println("Stack :"+actionInvocation.getStack().size());
System.out.println("Stack :"+actionInvocation.getStack().VALUE_STACK);
params =  actionInvocation.getStack().getContext();
itr = params.entrySet().iterator();
while(itr.hasNext()) {
    Object element = itr.next(); 
    System.out.print(" --> "+element + " ");
    Map.Entry pairs = (Map.Entry)itr.next();
System.out.println(pairs.getKey() + " = " + pairs.getValue());
}

System.out.println(" Action Name  : "+actionInvocation.getAction().toString());
String result = actionInvocation.invoke();
System.out.println(" Result : "+ result);

System.out.println("CustomInterceptor, after invocation.invoke()...");

return result;
}

}

      Struts2 Interceptor Read Parameter in interceptor class


in struts.xml file
in one common package.

<interceptors> 
            <interceptor name="crunchPrepInterceptor" class="com.googleforjava.thinksharp.interceptorsPrep.GatePass" />
            <interceptor-stack name="thinksharpPrepStack">
                <interceptor-ref name="thinksharpPrepInterceptor"/>
                <interceptor-ref name="defaultStack" />
            </interceptor-stack>
        </interceptors>
        <default-interceptor-ref name="thinksharpPrepStack"></default-interceptor-ref> 



in interceptor class:

 HttpServletResponse response = (HttpServletResponse) invocation.getInvocationContext().get(StrutsStatics.HTTP_RESPONSE);

Map sessionMap = actionInvocation.getInvocationContext().getSession();

String className = actionInvocation.getAction().getClass().getName();

System.out.println("Stack :"+actionInvocation.getStack().size());

System.out.println("Stack :"+actionInvocation.getStack().VALUE_STACK);

HttpServletRequest request = ServletActionContext.getRequest();

System.out.println(" Action Name  : "+actionInvocation.getAction().toString());

LoginUserBO loginUserBO=(LoginUserBO) sessionMap.get("user");

System.out.println("\n\n\n\n B4 Invocation Interceptor \n Class Name is: "+className);

if(loginUserBO==null){

System.out.println("\n\n User Object is null ");

}else{

userDetails(loginUserBO);

}

String result=actionInvocation.invoke();

sessionMap = actionInvocation.getInvocationContext().getSession();

 loginUserBO=(LoginUserBO) sessionMap.get("user");

System.out.println("\n\n\n After Invocation Interceptor Result is: "+result);

if(loginUserBO==null){

System.out.println("\n\n User Object is null ");

}else{

userDetails(loginUserBO);

}

return result;

}

  private void userDetails(LoginUserBO loginUserBO)

  {

  System.out.println("\n\n User Name is: "+loginUserBO.getFirst_name()+" User Role Id is :"+loginUserBO.getRole_id());

  }