PostConstruct (Java EE 5)

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SUMMARY: REQUIRED | OPTIONAL

DETAIL: ELEMENT

javax.annotation Annotation Type PostConstruct

@Documented @Retention(value=RUNTIME) @Target(value=METHOD) public @interface PostConstruct

Implements: Annotation

@Documented
@Retention(value=RUNTIME)
@Target(value=METHOD)

PostConstruct 注释用于在依赖关系注入完成之后需要执行的方法上，以执行任何初始化。此方法必须在将类放入服务之前调用。支持依赖关系注入的所有类都必须支持此注释。即使类没有请求注入任何资源，用 PostConstruct 注释的方法也必须被调用。只有一个方法可以用此注释进行注释。应用 PostConstruct 注释的方法必须遵守以下所有标准：该方法不得有任何参数，除非是在 EJB 拦截器 (interceptor) 的情况下，根据 EJB 规范的定义，在这种情况下它将带有一个 InvocationContext 对象；该方法的返回类型必须为 void；该方法不得抛出已检查异常；应用 PostConstruct 的方法可以是 public、protected、package private 或 private；除了应用程序客户端之外，该方法不能是 static；该方法可以是 final；如果该方法抛出未检查异常，那么不得将类放入服务中，除非是能够处理异常并可从中恢复的 EJB。

since	1.0
See also	javax.annotation.PreDestroy, javax.annotation.Resource

英文文档：

The PostConstruct annotation is used on a method that needs to be executed after dependency injection is done to perform any initialization. This method MUST be invoked before the class is put into service. This annotation MUST be supported on all classes that support dependency injection. The method annotated with PostConstruct MUST be invoked even if the class does not request any resources to be injected. Only one method can be annotated with this annotation. The method on which the PostConstruct annotation is applied MUST fulfill all of the following criteria - - The method MUST NOT have any parameters except in the case of EJB interceptors in which case it takes an InvocationC ontext object as defined by the EJB specification. - The return type of the method MUST be void. - The method MUST NOT throw a checked exception. - The method on which PostConstruct is applied MAY be public, protected, package private or private. - The method MUST NOT be static except for the application client. - The method MAY be final. - If the method throws an unchecked exception the class MUST NOT be put into service except in the case of EJBs where the EJB can handle exceptions and even recover from them.

Since:: 1.0
See Also:: PreDestroy, Resource