[HaBo]

import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;

import javax.portlet.PortletResponse;

import javax.servlet.http.HttpServletResponse;



import com.liferay.portal.util.PortalUtil;
import com.sun.faces.portlet.ExternalContextImpl;

public class MyClass implements
        PhaseListener {


....    

    public void beforePhase(PhaseEvent event) {
        ExternalContextImpl ctx = (ExternalContextImpl) event.getFacesContext()
                .getExternalContext();
     
....     

            // Response absenden
            HttpServletResponse resp = PortalUtil
                    .getHttpServletResponse((PortletResponse) ctx.getResponse());
            resp.setContentType("application/json");
            resp.setHeader("Cache-Control", "no-store");
            resp.setCharacterEncoding("UTF-8");

            PrintWriter pw;
            try {
                pw = resp.getWriter();

                pw.write(getJSONData(par1, par2, par3));
            } catch (IOException e) {
                
            }

        }


    
}