object - 如何获取特定 cdi 会话范围 bean 的所有实例

Question

我有一个 @SessionScoped cdi bean，用于跟踪我的 Web 应用程序中的用户会话信息。有没有办法从另一个 @ApplicationScoped bean 中找到这个 bean 的所有对象？

Answer 1

You cannot do this out of the box. Java EE forbid this kind of things for security reason.

Now you can imagine a more elaborate approaches to keep track of these session beans at your application scope level. The cleanest way would be to produce them from an @ApplicationScoped bean :

@ApplicationScoped
public class Registry {
  private List<SessionData> data = new ArrayList<>;

  @Produces
  @SessionScoped
  public SessionData produceSessionData() {
    SessionData ret = new SessionData();
    data.add(ret);
    return ret;
  }

  public void cleanSessionData(@Disposes SessionData toClean) {
    data.remove(toClean);
  }
}

Note the @Dispose method which will be called when your produced bean has ended its lifecycle. A convenient way to keep your list up to date and avoid extra memory usage.