Dependency injection in Spring MVC? - spring

Question

I am trying to use dependency injection in my Spring MVC web application. I have a function like this in my controller
#RequestMapping(value = "/stockgoogle/", method = RequestMethod.GET)
public #ResponseBody Stock stockGoogle(Locale locale, Model model) {
StockDaoImpl si = new StockDaoImpl();
//al=s.listCurrent(id);
Stock s=si.listGoogle();
System.out.println("reached here");
model.addAttribute("s", s );
return s;
}
I want to dependency inject StockDaoImpl. Can you please tell me how I can do this. I have been trying to read but most of the explainations are very complex. Should I use #Autowired ? Where should I put it? Can you please help.

Answer 1

You can inject it through the Controller's constructor
class YourController{
private final StockDao dao;
#Autowired
public YourController(StockDao dao){
this.dao = dao;
}
}
And now StockDaoImpl has to be defined as a Bean of course,
#Bean
public StockDao stockDao(){
return new StockDaoImpl();
}
Another way for doing it would be defining StockDaoImpl as a Component

Answer 2

Add below config in Spring config file(for example root-context.xml)
then in your controller, you like below code
class TestController{
#Autowired
private StockDao stockDao;
}

Answer 3

With spring-4 you can directly inject in given way :
#Autowired
private StockDao stockDao;
public #ResponseBody Stock stockGoogle(Locale locale, Model model) {
//al=s.listCurrent(id);
Stock s = stockDao.listGoogle();
System.out.println("reached here");
model.addAttribute("s", s );
return s;
}
Here
StockDao will contain method signature
StockDaoImpl implements StockDao and definition of methods
Autowired will inject that Dao and you can use its method.