@RequestMapping(value="/")
public String app(Model model,RedirectAttributes rm) throws IOException{
    UserCO userCO= new UserCO();
    userCO.setEmail("rptdbay@gmail.com");
    rm.addFlashAttribute("flashkey", "flashvalue");
    rm.addFlashAttribute("userCO", userCO);
    return "redirect:/controller1";
}

@RequestMapping(value="/controller1")
public String app1(Model model,HttpServletRequest request) throws IOException{
    System.out.println("=====================================");
    System.out.println("In Controller 1");
    Map md = model.asMap();
    for (Object modelKey : md.keySet()) {
        Object modelValue = md.get(modelKey);
        System.out.println("Model data =="+ modelKey + " -- " + modelValue);
    }

    java.util.Enumeration<String> reqEnum = request.getParameterNames();
    while (reqEnum.hasMoreElements()) {
        String s = reqEnum.nextElement();
        System.out.println("Request data =="+ s+" : "+ request.getParameter(s));
    }


    return "redirect:/controller2";
}



@RequestMapping(value="/controller2")
public String app2(Model model,HttpServletRequest request) throws IOException{
    System.out.println("=====================================");
    System.out.println("In Controller 2");
    Map md = model.asMap();
    for (Object modelKey : md.keySet()) {
        Object modelValue = md.get(modelKey);
        System.out.println("Model data =="+ modelKey + " -- " + modelValue);
    }

    java.util.Enumeration<String> reqEnum = request.getParameterNames();
    while (reqEnum.hasMoreElements()) {
        String s = reqEnum.nextElement();
        System.out.println("Request data =="+ s+" : "+ request.getParameter(s));
    }


    return "redirect:/controller3";
}