org.springframework.beans.BeanInstantiationException：无法实例化[org.springframework.ui.Model]：指定的类是接口

Question

I am using spring boot. My dao implementation is :

public void saveDetails(Proforma_Invoice proforma) {
    Session session = null;
    Transaction tx = null;
    try {
        session = sessionFactory.openSession();
        tx = session.beginTransaction();
        session.saveOrUpdate(proforma);
        tx.commit();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (session != null && session.isOpen())
            session.flush();
        if (session != null && session.isOpen())
            session.close();
    }
}

My controller is :

 @RequestMapping(value = "/enquiry", method = RequestMethod.GET)
    public ModelAndView getEnquiryScreen(Model model, Item_entity item, Integer item_code, vendor_entity vendor) {
        System.out.println("Controller is starting..");
        ModelAndView mav = new ModelAndView("enquiry_Screen");
        return mav;
    }

    @RequestMapping(value = "/enquiry", method = RequestMethod.POST)
    public ModelAndView demo(@ModelAttribute("enquiry") Model model, Item_entity item, Integer item_code,
            vendor_entity vendor, Proforma_Invoice proforma) {
        System.out.println("Controller is starting..");
        ModelAndView mav = new ModelAndView("enquiry_Screen"););
        return mav;
    }

Using these when i saving data then i got error :

2019-03-12 09:45:34.352 ERROR 7256 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.ui.Model]: Specified class is an interface] with root cause

org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.ui.Model]: Specified class is an interface

Please see the issue. and help me to solve the issue.

Answer 1

You're trying to mix using a Model as a controller parameter and using @ModelAttribute . @ModelAttribute is used when you have a form object that contains parameters from the incoming request and you want Spring to copy those parameters into an instance of the object. Either use a form object for your POST mapping (a good idea) or drop the annotation to use Model .