[英]Method with annotation @PostConstruct (javax) doesn't call
Is it possible to call a specific initialization method right after calling the constructor using annotations from javax?是否可以在使用 javax 中的注释调用构造函数后立即调用特定的初始化方法?
I put the @Inject
annotation (javax.inject.Inject)
over the field that I want to initialize in the method with the @PostConstruct
annotation (javax.annotation.PostConstruct)
right after the constructor is called, but this init method is not called and NPE crashes.在调用构造函数后,我将
@Inject
注释(javax.inject.Inject)
放在要在方法中使用@PostConstruct
注释(javax.annotation.PostConstruct)
初始化的字段上,但未调用此 init 方法和 NPE 崩溃。
public class ClassChild extends ClassParent{
@Inject
private SomeService someService;
@PostConstruct
public void init(){
someService = new SomeService(getSomeValues()) // getSomeValues() a method from parent
}
Am I using these annotations correctly?我是否正确使用了这些注释? What is the problem?
问题是什么? How to call the init() method right after calling the ClassChild constructor?
如何在调用 ClassChild 构造函数后立即调用 init() 方法? I would be very grateful for any help!
如果有任何帮助,我将不胜感激!
Your ClassChild
is not a managed object (eg a @Component
in Spring), so neither @Inject
nor @PostConstruct
will work.您的
ClassChild
不是托管的 object(例如 Spring 中的@Component
),因此@Inject
和@PostConstruct
都不起作用。 You're not supposed to call the constructor, you need to have the framework initialize ClassChild
, after which the framework will also call the @PostConstruct
method.您不应该调用构造函数,您需要让框架初始化
ClassChild
,之后框架还将调用@PostConstruct
方法。
Note that both @PostConstruct and @PreDestroy annotations are part of Java EE.请注意,@PostConstruct 和 @PreDestroy 注释都是 Java EE 的一部分。 And since Java EE has been deprecated in Java 9 and removed in Java 11 we have to add an additional dependency to use these annotations:
并且由于 Java EE 已在 Java 9 中被弃用并在 Java 11 中被删除,我们必须添加额外的依赖项来使用这些注释:
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>javax.annotation-api</artifactId>
<version>1.3.2</version>
</dependency>
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