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.

被声明为

@ManagedBean
@ViewScoped

1. 获取ID集(以准备进行删除操作).
2. 通过JSF，将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，因此我尝试将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(已检查)设置的值不再可用.

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

我必须使用Conversation.begin()和Conversation.end()方法吗?

如果是这样，在哪里可以调用它们?

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

推荐答案

如果可以升级到JSF 2.2，请立即执行.它提供了本机 @ViewScoped 批注CDI.

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 ，它会带来自己的与CDI兼容的

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 {
    // ...
}

另一种替代方法是安装 MyFaces CODI ，它透明地桥接了JSF 2.0/2.1 @ViewScoped CDI.这样只会将自动生成的请求参数添加到URL(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 {
    // ...
}

如果您确实需要使用@ConversationScoped，那么您确实需要手动开始和结束它.您需要@Inject一个 Conversation ，并在会话的最新步骤中在@PostConstruct和end()中调用begin()，通常是一种重定向到新视图的操作方法.

If you really need to use @ConversationScoped, then you indeed need to maunally 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";
    }

}

另请参见:

• 如何选择正确的bean作用域?

See also:

• How to choose the right bean scope?

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