CDI Injection into a FacesConverter

问题

From just a few searches, this seems like a problem that has been around for a while. I have written a FacesConverter that looks like the following. The object Category is a JPA entity and CategoryControl is the DAO that fetches it.

@FacesConverter(value = \"categoryConverter\")
public class CategoryConverter implements Converter {

@Inject private CategoryControl cc;

public CategoryConverter() { }

@Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
    if (cc != null) return cc.getByName(value);
    System.out.println(\"CategoryConverter().getAsObject(): no injection!\");
    return null;
}

@Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
    if (!(value instanceof Category)) return null;
    return ((Category) value).getName();
}

}

As you probably guessed by now, I never get the injection. I got this workaround from this page, which looks like this.:

Workaround for this problem: create this method in your localeController: 

public Converter getConverter() 
{ 
    return   FacesContext.getCurrentInstance().getApplication().createConverter(\"localeConverter\"); 
} 

and use converter=\"#{localeController.converter}\" in your h:selectOneMenu.

However I can\'t make this work either. My backing bean creates and returns a converter all right, but it doesn\'t get the object injected into it.

I am using MyFaces CODI 1.0.1. With the current GlassFish/Weld container. Can anyone suggest a solution before I re-code to not use a Converter?

回答1:

Replace

@FacesConverter(value = "categoryConverter")

@Named

and use

<h:inputSomething converter="#{categoryConverter}" />

<f:converter binding="#{categoryConverter}" />

instead of

<h:inputSomething converter="categoryConverter" />

<f:converter converterId="categoryConverter" />

By the way, similar problem exist for @EJB inside a @FacesConverter. It however offers a way to be grabbed by JNDI manually. See also Communication in JSF 2.0 - Getting an EJB in @FacesConverter and @FacesValidator. This way you can use a @FacesConverter(forClass=Category.class) without manually defining it everytime. Unfortunately I can't tell from top of head how to realize that for CDI beans.

Update: if you happen to use JSF utility library OmniFaces, since version 1.6 is adds transparent support for using @Inject and @EJB in a @FacesConverter class without any additional configuration or annotations. See also the CDI @FacesConverter showcase example.

回答2:

The @Inject Annotation only works in CDI managed instances. If you want to use CDI features inside a non-CDI managed instance (Like a JSF Validator or a JSF Converter) you can just programm against the CDI API.

This works only in at least Java EE 7 + CDI 1.1 server.

@FacesValidator("userNameValidator")
public class UserNameValidator implements Validator {

    private UserService userService;

    public UserNameValidator(){
        this.userService = CDI.current().select(UserService.class).get();
    }

    @Override
    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
     ....
    }
}

https://docs.oracle.com/javaee/7/api/javax/enterprise/inject/spi/CDI.html

With all the AnnotationHell in Java EE people forget how to code.

回答3:

Just use @Advanced of CODI for your @FacesConverter see the Wiki.

As soon as a converter or a validator is annotated with @Advanced it's possible to use @Inject.

回答4:

Per BalusC's answer here, I decided to add JSF (requestscoped) managed beans that only contained @FacesConverter and Converter to resolve this issue in my app, since I'm migrating from JSF managed beans to CDI managed beans.

I tried CODI @Advanced against @FacesConverter, but it does not inject the bean at all.

来源：https://stackoverflow.com/questions/7531449/cdi-injection-into-a-facesconverter

标签

jsf-2

cdi

myfaces