渴望ApplicationScoped托管bean构建多次 [英] Eager ApplicationScoped managed beans constructed multiple times

问题描述

我有一堆渴望 ApplicationScoped 托管bean。其中一些是通过 ManagedProperty 注释注入其他注释，形成依赖树。每个依赖bean在构造之后操纵它的父级。

I have a bunch of eager ApplicationScoped managed beans. Some of them are injected into others by the ManagedProperty annotation, forming a tree of dependencies. Each depending bean manipulates its parent after construction.

然而，似乎为每次注入创建了一个新实例，从而使之前的操作被撤消。据我了解，只应创建一次 ApplicationScoped bean。我误解了或者为什么会这样？是因为他们渴望？

However, it seems like a new instance is created for each injection, thus making previous manipulations undone. To my understanding, an ApplicationScoped bean should only be created once. Have I misunderstood or why is this happening? Is it because they are eager?

这是一个例子：

package example;

import javax.annotation.PostConstruct;
import javax.faces.bean.ApplicationScoped;
import javax.faces.bean.ManagedBean;

@ManagedBean(eager = true)
@ApplicationScoped
public class ParentBean
{
    static int initCount = 0;

    // ...

    @PostConstruct
    public void init()
    {
        ++initCount; // Will end up being between 1 and 3. Expected always 1.

        // ...
    }
}

Child1Bean.java

Child1Bean.java

package example;

import javax.annotation.PostConstruct;
import javax.faces.bean.ApplicationScoped;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;

@ManagedBean(eager = true)
@ApplicationScoped
public class Child1Bean
{
    @ManagedProperty("#{parentBean}") ParentBean parentBean;

    public ParentBean getParentBean()
    {
        return parentBean;
    }

    public void setParentBean(ParentBean parentBean)
    {
        this.parentBean = parentBean;
    }

    @PostConstruct
    public void init()
    {
        // manipulate parentBean
    }
}

Child2Bean.java

Child2Bean.java

package example;

import javax.annotation.PostConstruct;
import javax.faces.bean.ApplicationScoped;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;

@ManagedBean(eager = true)
@ApplicationScoped
public class Child2Bean
{
    @ManagedProperty("#{parentBean}") ParentBean parentBean;

    public ParentBean getParentBean()
    {
        return parentBean;
    }

    public void setParentBean(ParentBean parentBean)
    {
        this.parentBean = parentBean;
    }

    @PostConstruct
    public void init()
    {
        // manipulate parentBean
    }
}

推荐答案

我希望在Tomcat 8 + Mojarra 2.2.0上解决这个问题。
在我的情况下，我刚从web.xml中删除了监听器声明

I have hopefully resolved this problem on Tomcat 8 + Mojarra 2.2.0. In my case I just removed listener declaration from web.xml

<listener>
    <listener-class>com.sun.faces.config.ConfigureListener</listener-class>
</listener>

之后似乎会调用构造函数。

Constructor seems to be called once afterwards.

关于听众的录入，有一部分BalusC回答了这个问题。

About listener entry, there is a part of BalusC answer of this question.

在任何情况下，在web.xml中显式注册Mojarra的ConfigureListener实际上只需要解决旧的buggy服务器例如GlassFish v3和Jetty未能在Mojarra的TLD文件中找到听众。当部署到一个体面的服务器时，整个条目是不必要的。

In any case, the explicit registration of Mojarra's ConfigureListener in web.xml is actually only necessary to workaround old buggy servers such as GlassFish v3 and Jetty who failed to find the listener in Mojarra's TLD file. When deployed to a decent server, the whole entry is unnecessary.

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