java - Interceptor can't access Action Parameters -

i'm creating example struts2 interceptors. created simple login page , used custom interceptor class encrypt input. interceptor reading values of input valuestack null.

i don't understand doing wrong. suppose struts.xml , interceptor class enough data this. if need more of code, please tell.

struts.xml

<?xml version="1.0" encoding="utf-8"?> <!doctype struts public "-//apache software foundation//dtd struts configuration 2.0//en" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts>     <constant name="struts.devmode" value="true" />     <package name="mypackage" extends="struts-default">     <interceptors>             <interceptor name="encrypt" class="com.keyur.struts2.interceptors.encryptdecryptinterceptor"/>         </interceptors>         <action name="validatoraction" class="com.keyur.struts2.actionclasses.validatorclass" method="execute">         <interceptor-ref name="encrypt"></interceptor-ref>         <result name="success">/success.jsp</result>         <result name="input">/index.jsp</result>         </action>     </package> </struts> 

interceptor .java file

package com.keyur.struts2.interceptors;  import com.keyur.struts2.actionclasses.validatorclass; import com.keyur.struts2.beans.encryptordecryptor; import com.opensymphony.xwork2.actioninvocation; import com.opensymphony.xwork2.interceptor.interceptor; import com.opensymphony.xwork2.util.valuestack;  public class encryptdecryptinterceptor implements interceptor {          encryptordecryptor encdec = new encryptordecryptor();      @override     public void destroy() {         // todo auto-generated method stub      }      @override     public void init() {         // todo auto-generated method stub      }      @override     public string intercept(actioninvocation arg0) throws exception {         // todo auto-generated method stub          string result = arg0.invoke();          valuestack stack = arg0.getstack();         string username = stack.findstring("username");         string password = stack.findstring("password");          system.out.println("username: "+((validatorclass)stack.peek()).getusername());         system.out.println("password: "+((validatorclass)stack.peek()).getpassword());         //system.out.println(username);         //system.out.println(password);          //stack.set("username", encdec.encrypttext(username));         //stack.set("password", encdec.encrypttext(password));          return result;     } } 

encryptordecryptor separate class have defined , working correctly on it's own.

if want access parameters, params interceptor should go first

<action name="validatoraction" class="com.keyur.struts2.actionclasses.validatorclass" method="execute">    <interceptor-ref name="params"></interceptor-ref>    <interceptor-ref name="encrypt"></interceptor-ref>    <interceptor-ref name="defaultstack"></interceptor-ref>    <result name="success">/success.jsp</result>    <result name="input">/index.jsp</result> </action> 

your problem parameters don't go valuestack, , should them action context.

map params = actioncontext.getcontext().getparameters(); 

but after params interceptor should there.