@PostConstruct 注解

Posted 2020-07-01 SonoFelice——棣琦

@PostConstruct 注解

 1 /*
 2  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 3  * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 4 24  */
25 
26 package javax.annotation;
27 
28 import java.lang.annotation.*;
29 import static java.lang.annotation.ElementType.*;
30 import static java.lang.annotation.RetentionPolicy.*;
31 
32 /**
33  * The PostConstruct annotation is used on a method that needs to be executed
34  * after dependency injection is done to perform any initialization. This
35  * method MUST be invoked before the class is put into service. This
36  * annotation MUST be supported on all classes that support dependency
37  * injection. The method annotated with PostConstruct MUST be invoked even
38  * if the class does not request any resources to be injected. Only one
39  * method can be annotated with this annotation. The method on which the
40  * PostConstruct annotation is applied MUST fulfill all of the following
41  * criteria 
42 - The method MUST NOT have any parameters except in the case of EJB
43  * interceptors   in which case it takes an InvocationC ontext object as
44  * defined by the EJB   specification.
45  * - The return type of the method MUST be void.
46  * - The method MUST NOT throw a checked exception.
47  * - The method on which PostConstruct is applied MAY be public, protected,
48  * package private or private.
49  * - The method MUST NOT be static except for the application client.
50  * - The method MAY be final.
51  * - If the method throws an unchecked exception the class MUST NOT be put into
52  * service except in the case of EJBs where the EJB can handle exceptions and
53  * even   recover from them.
54  * @since Common Annotations 1.0
55  * @see javax.annotation.PreDestroy
56  * @see javax.annotation.Resource
57  */
58 @Documented
59 @Retention (RUNTIME)
60 @Target(METHOD)
61 public @interface PostConstruct {
62 }