Enabling EJB Injection into Vaadin 7 UI via Usage of Vaadin-CDI-Integration Addon

问题

I wasn't able to successfully integrate the official Vaadin-CDI-Integration-Addon, since after finishing the official integration instructions, the following Exception was thrown in case I reloaded the already published URL localhost:8080/App/?restartApplication.

javax.servlet.ServletException: com.vaadin.server.ServiceException: 
java.lang.IllegalStateException: UI id has already been defined

---

The following little workaround is a tested, working solution, which completes the official instructions.

回答1:

You have to work off the following steps to successfully integrate the official CDI-Integration-Addon into your Vaadin project.

• Do exactly as stated in the official how-to.
• Remove the ?restartApplication parameter from the URL. This avoids the Exception.
• Inject the EJB as shown in the listing below.
• Keep in mind to restart your application manually if necessary!

---

@CDIUI
public class ExampleCDIUI extends UI {

    @Inject
    MyLocalBeanInterface myBean;

    @Override
    public void init(VaadinRequest request) {
        Label label = new Label("Hello Vaadin user");
        setContent(label);

        // myBean should be accessible now.

    }

}

That's it. I hope this helps :-)

来源：https://stackoverflow.com/questions/17929089/enabling-ejb-injection-into-vaadin-7-ui-via-usage-of-vaadin-cdi-integration-addo