Issue
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");
}
}
Solution
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.
Answered By - gkamal
Answer Checked By - Marilyn (JavaFixing Volunteer)
