在Spring中创建URL的最佳方法

Question

Let's say we have controllers with URL mappings like movie/{id}-{title} , actor/{id}-{name} , etc. These mappings identify some objects in our app, mostly entities - we can say it's a RESTful service.

I'm looking for a solution as to where I should put methods responsible for creation of those URIs. I think that creating them in multiple JSP files and some other places (redirection, etc.) is redundant.

First, what I thought about was creating some interface with method public URI getURI() that classes that will be used in controllers will implement. But, in my opinion, that would involve too much into entity - I prefer entities just to represent data and contain only methods to change state.

My second idea was to create a URIService with overloaded methods like URI getURI(Movie m) and URI getURI(Actor a) , but there will be a problem with the choice of overloading method at compile time. For example, in EL in JSP that wouldn't work well, as the solution would be naming methods differently.

I don't want to reinvent the wheel, so maybe you know or use some solution to that problem?

Answer 1

How enterprisey do you want the solution to be? (I'm just half kidding)

Here's a solution: Have a service that has a method like URI getURI(Object o) . This method will check if the object passed belongs to a class with an annotation that specifies the URI path. Example annotation:

public @interface PathTemplate {String value();}

Example class with the annotation:

@PathTemplate("/movie/{title}-{id}")
public class Movie {
  private int id;private String title;
  // getters and setters too
}

Now, the getURI method will see that the parameter object's class has a PathTemplate annotation and will interpolate the parameters using bean introspection. Voila! Expandable and relatively decoupled URI generation.