带注释的方法或带注释的类中的方法的切入点 [英] Pointcut for annotated methods or methods in annotated classes

问题描述

我需要一个用@X 注释的类中的方法或用@X 注释的方法的切入点.我还需要注释对象.如果类和方法都被注释我更喜欢将方法注释作为参数.

I need a pointcut for methods in classes annotated with @X or methods annotated with @X. I also need the annotation object. If both the class and the method are annotated I prefer to get the method annotation as argument.

我尝试了以下操作，这会产生不一致的绑定"警告.(为什么不直接将它们设置为 null?)

I tried the following, which creates an "inconsistent binding" warning. (Why not just set them null?)

@Around("@annotation(methodLevelX) || @within(classLevelX)")
public Object advise(ProceedingJoinPoint pjp, X methodLevelX, X classLevelX)

以下创建了一个参数 x 跨'||'的模糊绑定在切入点"警告.(这在我看来不一定有意义:为什么不绑定第一个短路评估?)

The following creates a "ambiguous binding of parameter(s) x across '||' in pointcut" warning. (Which does not necessarily make sense in my opinion: Why not bind the first short circuited evaluation?)

@Around("@annotation(x) || @within(x)")
public Object advise(ProceedingJoinPoint pjp, X x)

如果存在类和方法注释，则将之前的尝试一分为二自然会导致两个方法调用.

Splitting the previous attempt in two naturally results in two method calls if class and method annotations are present.

我知道我可以通过反射和我想要的注释来获取方法和类，像这样的切入点:

I know I could just get the method and class with reflection and my desired annotation with a pointcut like this:

@Around("@annotation(com.package.X) || @within(com.package.X)")

但我不想这样做.

有没有什么一个切入点，一个方法，一个注解参数"的解决方案，我的需求不需要反射?

推荐答案

不完全，但差不多.您将需要两个切入点、两个通知，但您可以将工作委托给一个方法.下面是它的样子:

Not quite, but almost. You will need two pointcuts, two advices, but you can delegate the work to a single method. Here's how it would look like:

@Aspect
public class AnyAspectName {

    @Pointcut("execution(@X * *.*(..))")
    void annotatedMethod() {}

    @Pointcut("execution(* (@X *).*(..))")
    void methodOfAnnotatedClass() {}

    @Around("annotatedMethod() && @annotation(methodLevelX)")
    public Object adviseAnnotatedMethods(ProceedingJoinPoint pjp, X methodLevelX) 
            throws Throwable {
        return aroundImplementation(pjp, methodLevelX);
    }

    @Around("methodOfAnnotatedClass() && !annotatedMethod() && @within(classLevelX)")
    public Object adviseMethodsOfAnnotatedClass(ProceedingJoinPoint pjp, X classLevelX) 
            throws Throwable {
        return aroundImplementation(pjp, classLevelX);
    }

    public Object aroundImplementation(ProceedingJoinPoint pjp, X annotation) 
            throws Throwable {
        return pjp.proceed();
    }

}

请注意，除了将 @annotation() 和 @within() 切入点分开之外，我还对结果切入点添加了限制，使它们不会太宽泛.我想你想要方法执行连接点，所以我添加了需要的切入点表达式，将它限制为方法执行.他们是匹配的

Note that besides splitting apart the @annotation() and @within() pointcuts, I added restrictions to the resulting pointcuts so that they aren't too broad. I suppose you want method execution join points, so I added the needed pointcut expressions that would restrict it to method execution. They are matching

1. 执行任何用 @X 注释的方法，在任何包中的任何类中的任何返回类型用于第一个建议
2. 在第二个用 @X 注释的任何类中执行具有任何返回类型的任何方法.

1. execution of any method annotated with @X with any return type in any class being in any package for the first advice
2. execution of any method with any return type in any class annotated with @X for the second.

进一步限制 @within(X) 和 @annotation(X) 就派上用场了，因为 @within(X) 本身会匹配

Further restricting @within(X) and @annotation(X) comes in handy, because @within(X) by itself would match

在类型中定义关联代码的任何连接点X

any join point where the associated code is defined in a type with an annotation of type X

包括method-execution、method-call、constructor-execution、constructor-call、预初始化、静态初始化、初始化、字段设置、字段获取、exception-handler，lock 类型的连接点(尽管并非所有连接点都对 around 建议有效).类似地，@annotation(X) 本身意味着

which would include method-execution, method-call, constructor-execution, constructor-call, pre-initialization, static initialization, initialization, field set, field get, exception-handler, lock type join points (not all join points are valid for around advices though). Similarly, @annotation(X) by itself would mean

主题具有 X

这也可能意味着前面提到的大部分连接点，具体取决于注释的目标类型.

which could also mean most of the previously mentioned join points, depending on the target type of your annotation.

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