如何在自定义Converter中访问EJB bean [英] How do I access EJB bean when inside a custom Converter

问题描述

从我的JSF调用此转换器。我已在 faces-config.xml

This converter is called from my JSF. I already register it inside faces-config.xml

public class ProjectConverter implements Converter{

    @EJB
    DocumentSBean sBean;

    @ManagedProperty(value="#{logging}")
    private Logging log;    

    public ProjectConverter(){
    }

    public Object getAsObject(FacesContext context, UIComponent component, String value) 
    {
        if(value.trim().equals("")){
            return null;
        }
        return sBean.getProjectById(value);

    }

    public String getAsString(FacesContext context, UIComponent component, Object value) 
    {
        if(value == null){
            return null;
        }
        return String.valueOf(((Project) value).getId());
    }
}

我遇到了 java。 lang.NullPointerException ，当我在 getAsObject（）时，主要原因是因为我的会话Bean sBean 为空。我不知道如何解决这个问题，我需要访问我的Session bean，以便我可以从我的数据库中查询

I ran into java.lang.NullPointerException, when I am in getAsObject(), the primary reason is because my Session Bean sBean is null. I dont know how to fix this, I need to access to my Session bean so that I can query from my database

推荐答案

As BalusC 说，注入仅适用于托管bean。但是，您可以在faces-config中将转换器声明为托管bean

As BalusC said, injection only works in managed beans. You can however declare your converter as a managed bean in your faces-config

<managed-bean>
   <managed-bean-name>myConverter</managed-bean-name>
   <managed-bean-class>com.example.MyConverter</managed-bean-class>
   <managed-bean-scope>request</managed-bean-scope>
</managed-bean>

稍后在带有el表达式的jsf组件中引用它：

And later reference it in a jsf component with an el expression:

<h:outputText value="#{myBean.value}" converter="#{myConverter}" />

这篇关于如何在自定义Converter中访问EJB bean的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！