java - Spring 自定义注解 : how to inherit attributes?

Question

我正在创建自己的自定义快捷方式注释，如 Spring Documentation 中所述:

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Transactional(value = "Custom", readOnly = true)
public @interface CustomTransactional {
}

有没有可能，通过我的自定义注释，我还可以设置任何其他属性，这些属性在 @Transactional 中可用？我希望能够使用我的注释，例如，像这样:

@CustomTransactional(propagation = Propagation.REQUIRED)
public class MyClass {

}

Answer 1

不，如果您想要必须以这种方式在自定义注释本身上设置的其他属性，那将行不通:

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Transactional(value = "Custom", readOnly = true, propagation = Propagation.REQUIRED)
public @interface CustomTransactional {
}

一个解决方案(不好的 :-) )可能是使用您在场景中看到的基本案例集定义多个注释:

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Transactional(value = "Custom", readOnly = true, propagation = Propagation.REQUIRED)
public @interface CustomTransactionalWithRequired {
}

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Transactional(value = "Custom", readOnly = true, propagation = Propagation.SUPPORTED)
public @interface CustomTransactionalWithSupported {
}