Question

I want to use a annotated prototype bean in my controller. But spring is creating a singleton bean instead. Here is the code for that:

@Component
@Scope("prototype")
public class LoginAction {

  private int counter;

  public LoginAction(){
    System.out.println(" counter is:" + counter);
  }
  public String getStr() {
    return " counter is:"+(++counter);
  }
}

Controller code:

@Controller
public class HomeController {
    @Autowired
    private LoginAction loginAction;

    @RequestMapping(value="/view", method=RequestMethod.GET)
    public ModelAndView display(HttpServletRequest req){
        ModelAndView mav = new ModelAndView("home");
        mav.addObject("loginAction", loginAction);
        return mav;
    }

    public void setLoginAction(LoginAction loginAction) {
        this.loginAction = loginAction;
    }

    public LoginAction getLoginAction() {
        return loginAction;
    }
    }

Velocity template:

 LoginAction counter: ${loginAction.str}

Spring config.xml has component scanning enabled:

    <context:annotation-config />
    <context:component-scan base-package="com.springheat" />
    <mvc:annotation-driven />

I’m getting an incremented count each time. Can’t figure out where am I going wrong!

Update

As suggested by @gkamal, I made HomeController webApplicationContext-aware and it solved the problem.

updated code:

@Controller
public class HomeController {

    @Autowired
    private WebApplicationContext context;

    @RequestMapping(value="/view", method=RequestMethod.GET)
    public ModelAndView display(HttpServletRequest req){
        ModelAndView mav = new ModelAndView("home");
        mav.addObject("loginAction", getLoginAction());
        return mav;
    }

    public LoginAction getLoginAction() {
        return (LoginAction) context.getBean("loginAction");
    }
}

Answer 1

Scope prototype means that every time you ask spring (getBean or dependency injection) for an instance it will create a new instance and give a reference to that.

In your example a new instance of LoginAction is created and injected into your HomeController . If you have another controller into which you inject LoginAction you will get a different instance.

If you want a different instance for each call – then you need to call getBean each time – injecting into a singleton bean will not achieve that.