如何在 JSF 2.0/2.1 中用 CDI 替换 @ManagedBean/@ViewScope [英] How to replace @ManagedBean / @ViewScope by CDI in JSF 2.0/2.1

问题描述

我目前正在使用 RichFaces 评估 Java EE 6/JSF 2.1.

I'm currently evaluating Java EE 6 / JSF 2.1 with RichFaces.

声明为

@ManagedBean
@ViewScoped

1. 获取 ID 集(准备删除操作等).
2. 通过 JSF 显示一个确认弹出窗口.
3. 如果用户确认，则调用 delete 方法并删除在步骤 1 中为其存储 ID 的行.

由于 CDI bean 没有 ViewScope，我尝试将 bean 声明为:

Since CDI beans don't have a ViewScope I tried to declare the bean as:

@Named
@ConversationScoped

现在处理在步骤 3 中失败.因为在步骤 1 中设置的值(已检查)不再可用.

Now the processing fails in step 3. because the value that was set in step 1 (checked that) is no longer available.

我是否必须使用 Conversation.begin() 和 Conversation.end() 方法?

Do I have to use Conversation.begin() and Conversation.end() methods?

如果是这样，哪里是调用它们的好地方?

If so, where would be good place to invoke them?

推荐答案

如果您可以升级到 JSF 2.2，请立即升级.它提供了一个原生的 @ViewScoped CDI 注释.

If you can upgrade to JSF 2.2, immediately do it. It offers a native @ViewScoped annotation for CDI.

import javax.faces.view.ViewScoped;
import javax.inject.Named;

@Named
@ViewScoped
public class Bean implements Serializable {
    // ...
}

或者，安装 OmniFaces，它带来了自己的 CDI 兼容 @ViewScoped，包括一个有效的 @PreDestroy(在 JSF @ViewScoped).

Alternatively, install OmniFaces which brings its own CDI compatible @ViewScoped, including a working @PreDestroy (which is broken on JSF @ViewScoped).

import javax.inject.Named;
import org.omnifaces.cdi.ViewScoped;

@Named
@ViewScoped
public class Bean implements Serializable {
    // ...
}

另一种选择是安装 MyFaces CODI，它透明地桥接 JSF 2.0/2.1 @ViewScoped 到 CDI.这只会向 URL 添加一个自动生成的请求参数(就像 @ConversationScoped 那样).

Another alternative is to install MyFaces CODI which transparently bridges JSF 2.0/2.1 @ViewScoped to CDI. This only adds an autogenerated request parameter to the URL (like @ConversationScoped would do).

import javax.faces.bean.ViewScoped;
import javax.inject.Named;

@Named
@ViewScoped
public class Bean implements Serializable {
    // ...
}

如果你真的需要使用@ConversationScoped，那么你确实需要手动开始和结束它.您需要 @Inject 一个 Conversation 并在最新的 @PostConstruct 和 end() 中调用 begin()对话的步骤，通常是重定向到新视图的操作方法.

If you really need to use @ConversationScoped, then you indeed need to manually begin and end it. You need to @Inject a Conversation and invoke begin() in the @PostConstruct and end() in the latest step of the conversation, usually an action method which redirects to a new view.

import javax.enterprise.context.Conversation;
import javax.enterprise.context.ConversationScoped;
import javax.inject.Named;

@Named
@ConversationScoped
public class Bean implements Serializable {

    @Inject
    private Conversation conversation;

    // ...

    @PostConstruct
    public void init() {
        conversation.begin();
    }

    public String submit() {
        // ...

        conversation.end();
        return "some.xhtml?faces-redirect=true";
    }

}

另见:

• 如何选择合适的 bean 范围?

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