焊接不是注射

Question

我正在尝试在java SE中设置一个非常简单的焊接实现.

我有扩展类:

public class MyExtension implements Extension {

    void beforeBeanDiscovery(@Observes BeforeBeanDiscovery bbd) {
        System.out.println("Starting scan...");
    }      
    <T> void processAnnotatedType(@Observes ProcessAnnotatedType<T> annotatedType, BeanManager beanManager) {
        System.out.println("Scanning type: " + annotatedType.getAnnotatedType().getJavaClass().getName());
    } 
    void afterBeanDiscovery(@Observes AfterBeanDiscovery abd) {
        System.out.println("Finished the scanning process");
    }

    public void main(@Observes ContainerInitialized event) {
        System.out.println("Starting application");
        new Test();
    }
}

然后我有一个我想要注入的简单类:

public class SimpleClass {
    public void doSomething() {
        System.out.println("Consider it done");
    }
}

最后我要把它注入的课程:

public class Test {

    @Inject
    private SimpleClass simple;

    @PostConstruct
    public void initialize() {
        simple.doSomething();
    }

    @PreDestroy
    public void stop() {
        System.out.println("Stopping");
    }
}

结果输出是:

80 [main] INFO org.jboss.weld.Version - WELD-000900 1.1.10 (Final)
272 [main] INFO org.jboss.weld.Bootstrap - WELD-000101 Transactional services not available. Injection of @Inject UserTransaction not available. Transactional observers will be invoked synchronously.
Starting scan...
Scanning type: test.Test
Scanning type: test.SimpleClass
Scanning type: test.MyExtension
640 [main] WARN org.jboss.weld.interceptor.util.InterceptionTypeRegistry - Class 'javax.ejb.PostActivate' not found, interception based on it is not enabled
640 [main] WARN org.jboss.weld.interceptor.util.InterceptionTypeRegistry - Class 'javax.ejb.PrePassivate' not found, interception based on it is not enabled
Finished the scanning process
Starting application

我希望在构造Test()时调用简单类,并调用应该输出预期文本的postconstruct方法.

我究竟做错了什么？

Answer 1

您的代码存在两个问题:

问题1:

CDI不管理使用的bean创建new.在大多数情况下,您需要@Inject a bean以使其生命周期由容器管理

问题2:

在大多数情况下,您不能将bean实例注入容器事件的观察者.这是因为事件在容器初始化时触发,即在它实际上可以开始管理对象生命周期之前.

您可以将容器初始化程序观察器直接挂接到Test类中.像这样的东西:

public class SimpleClass {
    public void doSomething() {
        System.out.println("Consider it done");
    }

   @PostConstruct
    public void initialize() {
        System.out.println("Starting");
    }

    @PreDestroy
    public void stop() {
        System.out.println("Stopping");
    }
}

public class Test {

    @Inject
    private SimpleClass simple;

    public void main(@Observes ContainerInitialized event) {
        System.out.println("Starting application");
        simple.doSomething();
    }       
}