如何在PhaseListener中@Inject

问题描述

我已将PhaseListener添加到faces-config.xml:

<lifecycle>
    <phase-listener>com.project.NotificationListener</phase-listener>
</lifecycle>

该类似乎很正确，因为它非常简单.

The class seems to be otherwise correct as it is pretty simple.

public class NotificationListener implements PhaseListener {

    @Inject
    private MyCDIStuff stuff;

    @Override
    public PhaseId getPhaseId() {
        return PhaseId.RENDER_RESPONSE;
    }

    @Override
    public void beforePhase(PhaseEvent event) {
        this.stuff.doStuff();
    }
}

正确调用了"beforePhase"方法，但是MyCDIStuff对象为null.我尝试对最有可能是不正确的类使用批注@Singleton，它也无法使注入工作.

The 'beforePhase' method gets called correctly, however the MyCDIStuff object is null. I tried using annotation @Singleton for the class which most likely was incorrect, and it didn't make the injection work either.

是否可以在PhaseListener中注入CDI管理的bean?

Is there a way to inject CDI managed beans in the PhaseListener?

推荐答案

在JSF 2.2之前，PhaseListener未注册为CDI注入目标.使用@Inject(和@EJB)在PhaseListener中实际上无效.您需要通过以编程方式评估引用@Named的(隐式)名称的EL表达式，或者通过JNDI和BeanManager笨拙地作为最后手段，来手动获取CDI托管的bean.

Before JSF 2.2, PhaseListeners are not registered as CDI injection targets. Using @Inject (and @EJB) has effectively no effect in PhaseListeners. You'd need to manually grab the CDI managed beans by programmatically evaluating an EL expression referencing the @Named's (implicit) name, or as last resort via JNDI and BeanManager which is quite clumsy.

因此，如果您不能升级到JSF 2.2(应该与任何与JSF 2.0/2.1和Servlet 3.0兼容的Web应用程序兼容)，那么最好的选择就是以编程方式评估引用@Named名称的EL表达式.假设您拥有

So, if you can't upgrade to JSF 2.2 (which should be compatible with any JSF 2.0/2.1 and Servlet 3.0 compatible web application), then your best bet is programmatically evaluating an EL expression referencing the @Named name. Assuming that you've a

@Named("stuff")
public class MyCDIStuff {}

然后应该这样做:

FacesContext context = event.getFacesContext();
MyCDIStuff stuff = context.getApplication().evaluateExpressionGet(context, "#{stuff}", MyCDIStuff.class);
// ...

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