Using Struts and XWork with JSP 2.0 and JSTL 1.1

S2/X1 and its taglib is oriented towards OGNL, which is using a value stack
for all action properties. These values are not direct available for the
expression language of JSP2/JSTL1.1.

However, it's easy to populate the request
attribute set, with all gettable properties of an action object. You need to provide
an interceptor that does the job, by register a PreResultListener which is
invoked after the return of Action.execute() but before the rendering of the result .

The interceptor below is using Jakarta BeanUtils. It first extracts all getters
of the current action, invokes them one at the time and stores the values into a map.
Then it iterates over the map and populates the request attribute set.
The double iteration is not needed, it's just there for clarity.

class ActionPropertyExportInterceptor

package com.whatever.interceptors;

import org,apache.struts2.StrutsStatics;
import com.opensymphony.xwork.Action;
import com.opensymphony.xwork.ActionInvocation;
import com.opensymphony.xwork.interceptor.AroundInterceptor;
import com.opensymphony.xwork.interceptor.PreResultListener;
import org.apache.commons.beanutils.PropertyUtils;
import javax.servlet.http.HttpServletRequest;
import java.beans.PropertyDescriptor;
import java.util.*;

/**
 * Populates HTTP Request Attributes with all gettable properties of the current action.
 */
public class ActionPropertyExportInterceptor extends AroundInterceptor {
    protected void before(ActionInvocation invocation) throws Exception {
        invocation.addPreResultListener( new PropertyExporter() );
    }
    protected void after(ActionInvocation dispatcher, String result) throws Exception { }

    public static class PropertyExporter implements PreResultListener {
        private static final List   ignore = Arrays.asList(new String[] {"class", "texts"}); //skip getClass,...

        //Invoked after Action.execute() but before Result
        //Calls all getters of the action and insert the values into the request
        public void beforeResult(ActionInvocation invocation, String resultCode) {
            Map                 props   = extractGetterPropertyValues( invocation.getAction() );
            HttpServletRequest  request = getRequest(invocation);
            for (Iterator it = props.entrySet().iterator(); it.hasNext();) {
                Map.Entry   e = (Map.Entry) it.next();
                request.setAttribute((String) e.getKey(), e.getValue());
            }
        }

        public Map extractGetterPropertyValues(Object bean) {
            PropertyDescriptor[]  descr = PropertyUtils.getPropertyDescriptors(bean);
            Map                   props = new HashMap();
            for (int i = 0; i < descr.length; i++) {
                PropertyDescriptor d = descr[i];
                if (d.getReadMethod() == null) continue;
                if (ignore.contains(d.getName())) continue;

                try {
                    props.put(d.getName(), PropertyUtils.getProperty(bean, d.getName()));
                } catch (Exception e) { }
            }
            return props;
        }

        public HttpServletRequest getRequest(ActionInvocation invocation) {
            return (HttpServletRequest) invocation.getInvocationContext().get(WebWorkStatics.HTTP_REQUEST);
        }
    }
}

Don't forget to declare the interceptor in your struts.xml file and insert it
into your interceptor stack.

struts.xml snippet

<interceptor name="export" class="com.whatever.interceptors.ActionPropertyExportInterceptor" />
. . .
<interceptor-stack name="standard-interceptors">
    <interceptor-ref name="timer" />
    <interceptor-ref name="logger" />
    <interceptor-ref name="params" />
*    <interceptor-ref name="export"/>*
    <interceptor-ref name="validateParams"/>
    <interceptor-ref name="awarePlugger" />
</interceptor-stack>

Your action need to provide getters for all properties that should be exported into the
request attribute set.

class ViewUser

public class ViewUser extends ActionSupport {
    private int                         id;
    private User                        user;

    public String execute() throws Exception {
        user = findUser( getId() );
        return Action.SUCCESS;
    }

    public  int   getId()          {return id;}
    public  void  setId(int id)    {this.id = id;}
*    public  User  getUser()        {return user;}*

    private User  findUser(int id) {...}
}

The User class might look like this

class User

import java.util.Date;
public class User {
    private int     id;
    private String  firstName, lastName, email;
    private String  street, zip, city;
    private Date    date;
    
    public String  getFirstName() {return firstName;}
    //..._getters and setters_...
}

Finally, using the samples above you can write your JSP2 page like this.

ViewUser.jsp

<%@ taglib prefix="c"   uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib prefix="fn"  uri="http://java.sun.com/jsp/jstl/functions" %>
<html>
<head>
    <title>Info about ${user.firstName}</title>
</head>
<body>
    <h1>Info about ${user.firstName} ${user.lastName} [OS:ID=${user.id}]</h1>
    <table border="1" cellspacing="0" cellpadding="2" width="90%" >
    <tr>
        <th>Name</th> <td>${user.firstName} ${user.lastName}</td>
    </tr>
    <tr>
        <th>Created</th> <td><fmt:formatDate value="${user.date}" pattern="yyyy-MM-dd HH:mm"/></td>
    </tr>
    <tr>
        <th>Email</th> <td>${user.email}</td>
    </tr>
    <tr>
        <th>Address</th> <td>${user.street} ${user.zip} ${fn:toUpperCase(user.city)}</td>
    </tr>
    </table>
</body>
</html>

Displaying validation errors with JSTL

<c:if test="${!empty fieldErrors || !empty actionErrors}">
  <div class="red">
    <ul>
      <c:forEach items="${fieldErrors}" var="fieldError">
        <c:forEach items="${fieldError.value}" var="error">
          <li>${error}</li>
        </c:forEach>
      </c:forEach>
      <c:forEach items="${actionErrors}" var="actionError">
        <li>${actionError}</li>
      </c:forEach>
    </ul>
  </div>
</c:if>