在CDI SessionScoped bean中注入HttpServletRequest

问题描述：

我有一个会话范围的CDI bean，我需要以某种方式访问这个bean的@PostConstruct方法中的 HttpServletRequest 对象。可能吗？我试图注入这样一个对象，但结果是：

I've got a session scoped CDI bean, and I need to somehow access the HttpServletRequest object in this bean's @PostConstruct method. Is it possible? I've tried to Inject such an object, but it results in:

WELD-001408 Unsatisfied dependencies for type [HttpServletRequest] with qualifiers     [@Default] at injection point [[field] @Inject ...]

据我了解在谷歌搜索时，Seam框架具有这样的功能，但我在GlassFish服务器上有一个标准的Java EE应用程序。

As I understood while googling, the Seam framework has such a functionality, but I have a standard Java EE application on a GlassFish server.

甚至可以以某种方式将请求传递给CDI bean的 @PostConstruct 方法？

Is it even possible to somehow pass the request to a CDI bean's @PostConstruct method?

答

根据你的评论，你想要访问用户主体。您可以像这样注入： @Inject Principal principal; 或 @Resource Principal principal; ，参见 Java EE 6教程。

As per your comment, you want access to the user principal. You can just inject it like this: @Inject Principal principal; or @Resource Principal principal;, see Java EE 6 Tutorial.

更新

我会回答您的直接问题。在Java EE 7（CDI 1.1）中，支持开箱即用的HttpServletRequest注入。但是，在Java EE 6（CDI 1.0）中，不支持开箱即用。要使其正常运行，请将以下课程添加到您的网络应用中：

I'll answer your direct question. In Java EE 7 (CDI 1.1) injection of HttpServletRequest is supported out of the box. In Java EE 6 (CDI 1.0) however, this is not supported out of the box. To get it working, include the class below into your web-app:

import javax.enterprise.inject.Produces;
import javax.servlet.ServletRequest;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class CDIServletRequestProducingListener implements ServletRequestListener {

    private static ThreadLocal<ServletRequest> SERVLET_REQUESTS = new ThreadLocal<>();

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        SERVLET_REQUESTS.set(sre.getServletRequest());
    }

    @Override
    public void requestDestroyed(ServletRequestEvent sre) {
        SERVLET_REQUESTS.remove();
    }

    @Produces
    private ServletRequest obtain() {
        return SERVLET_REQUESTS.get();
    }

}

注意：仅在GlassFish 3.1上测试.2.2

Note: Tested only on GlassFish 3.1.2.2

在CDI SessionScoped bean中注入HttpServletRequest

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