Spring-MVC : Creating a good infrastructure(configuration) and avoiding duplicates

Question

I am working on a Spring-MVC application since some time. Recently I ran into some problems with @Scheduled methods, and I noticed that the whole configuration is getting lo

Answer 1

There are a lot of things that can be improved with your code and configuration. Lets start with your dao, don't store the Session in a instance variable and I strongly suggest to use constructor injection for the required dependencies. Taking this into account your dao(s) should look something like this.

@Transactional
@Repository
public class CanvasDAOImpl implements CanvasDAO{

    private final SessionFactory sessionFactory;

    @Autowired
    public CanvasDAOImpl(SessionFactory sessionFactory) {
        this.sessionFactory=sessionFactory;
    }

   @overrride
   public returnType methodName(params..){
        Session session = this.sessionFactory.getCurrentSession();
        // Do stuff with the session.
    }
}

No more setters (especially not for the Session!) just a plain class. The same applies for the @Service classes.

@Service
@Transactional
public class CanvasServiceImpl implements CanvasService {

    private final CanvasDAO canvasDAO;

    public CanvasServiceImpl(CanvasDAO canvasDAO) {
        this.canvasDAO=canvasDAO;
    }

    //methods
}

In your configuration you have explicitly defined all your @Repository and @Service beans. You also have a which already detects all @Components. Remove all explicitly declared @Repository and @Service beans. This will really clean up your configuration!.

In your hibernate configuration the c3p0 and connection properties are useless as you are injecting a DataSource and hibernate is't managing it but Spring is. Remove those lines. Also to cleanup this configuration further instead of specifying each and every class it needs to proces add packagesToScan so it will automatically detect @Entity annotated beans.

is already implied by the use of so you can remove it as it basically duplicates things.

You have explicitly defined a RequestMappingHandlerMapping which doesn't do anything as there is already one registered by . It only takes up memory, the MappingJackson2HttpMessageConverter is registered automatically of Jackson2 is detected on the class path so no need to do that.

Chancing the Locale doesn't work for all URLs as you forgot to register the interceptor with the element.

When applying all that advice to your classes and configuration the remaining configuration looks like this.

    
    

    
        
            
        
    
    
        
        
    

    

    

    
        
        
    

    
        
        
        
        
        
        
        
    

    
    
        
               
        
        
            
                org.hibernate.dialect.PostgreSQL9Dialect
                false
             
                update
            
        
    

    

    

    
        
    



    


    
    
        
        
    


    
    
        
    

    
    
        
    

    
        
            
                
            
        
    

    

    
        
    

However you really should split things up in what is loaded by the ContextLoaderListener basically everything BUT @Controllers and what is loaded by the DispatcherServlet just @Controllers and web related beans.

So the servlet-context.xml should look something like this.

Then add what was removed and a (or modify it) to the root-context.xml.

    





    
    
    
    
    
    
    




    
           
    
    
        
            org.hibernate.dialect.PostgreSQL9Dialect
            false
         
            update
        
    







    

Remove the from your security-context.xml.

Finally let the DispatcherServlet load the servlet-context.xml instead of the security-context.xml.

Now as you aren't loading beans twice per context anymore you should have a reduced memory footprint and you shouldn't have 4 scheduled jobs any more. Also your Email class should, ideally, also be a Spring managed bean and I would suggest using the JavaMailSender API which simplifies sending emails.

So basically the task ahead for you is to mainly remove things, you will end up with less code and less configuration and still achieve the same.

For more hands-on-advice I'm for hire ;)...