CDI是什么?

import javax.inject.Named;

@Named
public class MessageServerBean {

    public String getMessage() {
        return "Hello World!";
    }
}
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       Message is : #{messageServerBean.message}<br>
        Message Server Bean is : #{messageServerBean}
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Message is : Hello World!
Message Server Bean is : eedemo.MessageServerBean@xxxxxxx
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@Named("itemProcessor")
@RequestScoped  //表示生命周期是request，每次request请求结束，生命就终止，也可以有Session或 Application等
public class ItemProcessor {

    @Inject
    private ItemDao itemDao; //表示ItemDao需要被注入

    ...
}
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public class PersonFactory {

  @Produces 
  @RequestScoped 
  public Person createPerson() {
     return new Person();
  }
}
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public void observeUserEvent(@Observes User user) {
 ...
}
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@Named
@SessionScoped
public class HelloWorld extends GenericComposer implements Serializable {
 
	@Inject @ComponentId("guestName") Textbox guestName;
	@Inject @ComponentId("sayHelloBtn") Button sayHelloBtn;
	@Inject @ComponentId("helloWindow") Window helloWindow;
 
	public void sayHello(@Observes @Events("sayHelloBtn.onClick") MouseEvent evt) {
		helloWindow.setTitle("Hello " + guestName.getValue());
	}
}

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