Spring MVC and custom tags

Question

I want to use spring-beans in my custom taglibs in a spring-mvc application. Cause TagLib-Instances aren't instantiated by spring, I can't use dependnecy-injection.

My next thought was to add the spring-context by an interceptor to the request and get it from request within the tag-class.

Is there a better way to use spring in taglibs? Is there something ready-to-use in spring? If theres not already customtag-support in spring-mvc, is there a way to populate an exisiting object with dependencies?

public class MyTag extends TagSupport {
  @Autowired 
  private MyObject object;

  public void setMyObject(MyObject myObject) {
    this.myObject = myObject;
  }

  public int doEndTag() {
    ApplicationContext context = request.getAttribute("context");
    context.populate(this);

    return object.doStuff();
  }
}

possible duplicate of How to inject spring beans into a jsp 2.0 SimpleTag ? — skaffman
– skaffman, Commented Jan 16, 2011 at 15:55
I know you probably don't want to hear this, but why are you performing operations that require spring beans in your view? It's best practice to keep your views as simple as possible. I'd try and attempt to do this in your controller if you haven't already... — Caps
– Caps, Commented Jan 19, 2011 at 3:32
I agree with @Caps. You should move that code to the Controller. — Benjamin Muschko
– Benjamin Muschko, Commented Apr 8, 2011 at 14:39

Pang · Accepted Answer · 2023-10-31 02:13:43Z

3

Finally, the working way to do this was to declare the fields that should be initiated by spring as static and let initiate one Tag-instance

public class MyTag extends TagSupport {
  private static MyObject myObject;

  @Autowired
  public void setMyObject(MyObject myObject) {
    MyTag.myObject = myObject;
  }

  public int doEndTag() {
    return object.doStuff();
  }
}

edited Oct 31, 2023 at 2:13

Pang

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answered May 9, 2012 at 10:39

mibutec

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Comments

Benjamin Muschko · Accepted Answer · 2011-04-08 14:47:16Z

You should prefer to put that logic into your controller. If you really need to do that you can write a utility class to retrieve beans from the application context.

public class AppContextUtil implements ApplicationContextAware 
{
    private static final AppContextUtil instance = new AppContextUtil();
    private ApplicationContext applicationContext;

    private AppContextUtil() {}

    public static AppContextUtil getInstance() 
    {
        return instance;
    }

    public <T> T getBean(Class<T> clazz) 
    {
        return applicationContext.getBean(clazz);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException 
    {
        this.applicationContext = applicationContext;
    }
}

You would then be able to retrieve your bean like this:

AppContextUtil.getInstance().getBean(MyObject.class);

Community · Accepted Answer · 2017-05-23 10:33:51Z

0

In your controller, put the object into the model.

The object can now be found in the HttpRequest object that is part of your tag.

Controller:

model.addAttribute("item", item);

Jsp File:

 <%= ((com.content.CmsItem)(request.getAttribute("item"))).getId() %>

If you must autowire, check out my solution on 'is there an elegant way to inject a spring managed bean into a java custom/simple tag'

edited May 23, 2017 at 10:33

CommunityBot

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answered Feb 28, 2012 at 19:05

Angus

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