@PostConstruct使用说明

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javax.annotation.PostConstruct的使用说明


以下是原文翻译,注释已经说明得很清楚了


The PostConstruct annotation is used on a method that needs to be executed after dependency injection is done to perform any initialization. 
PostConstruct注解使用在方法上,这个方法需要在依赖注入初始化之后执行。


This method MUST be invoked before the class is put into service. 
这个方法必须在该服务类使用之前执行。


This annotation MUST be supported on all classes that support dependency injection.
支持依赖注入的所有类都必须支持该注解。


The method annotated with PostConstruct MUST be invoked even if the class does not request any resources to be injected.
该方法必须执行,即使所在的类没有注入任何资源。


Only one method can be annotated with this annotation.
只能有一个方法使用该注解。


The method on which the PostConstruct annotation is applied MUST fulfill all of the following criteria - - 
使用了该注解的方法必须全部符合以下准则:


The method MUST NOT have any parameters except in the case of EJB interceptors in which case it takes an Invocation Context object as defined by the EJB specification. 
除EJB接口外不能拥有任何参数,


- The return type of the method MUST be void.
返回值必须是void


 - The method MUST NOT throw a checked exception. 
该方法不能抛出异常


- The method on which PostConstruct is applied MAY be public, protected, package private or private. 
可以使用public、protected等修饰符


- The method MUST NOT be static except for the application client.
方法不是是static修饰,除非是应用程序客户端


- The method MAY be final. 
方法可以使用final修饰


- 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.
方法如果抛出未知异常,则类绝不能作为service类,除非是可以处理异常甚至能恢复正常的EJB组件