java spring aop如何改变返回值
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How to change the return value by spring aop
提问by cleverUtd
I have a method with a return value in DAO layer, I want to change the return value by spring AOP, according different requirement,s and then send to corresponding method in SERVICE layer; but i don't know how to do so.
我在DAO层有一个返回值的方法，我想通过spring AOP改变返回值，根据不同的需求，然后发送到SERVICE层的相应方法；但我不知道该怎么做。
回答by Vikdor
You can apply an @Aroundaspect to the method whose return type should be modified. You can take a look at my blog poston how to add Spring AOP facet to a Spring application, then write an @Aroundaspect. I used this aspect for Memoizingresults of a method, but in your case, you would take the return value of ProceedingJoinPoint.proceed(), typecast it to appropriate class, then modify it and return it.
您可以将@Around方面应用于应修改其返回类型的方法。您可以查看我关于如何将 Spring AOP facet 添加到 Spring 应用程序的博客文章，然后编写一个@Around切面。我将此方面用于Memoizing方法的结果，但在您的情况下，您将获取 的返回值ProceedingJoinPoint.proceed()，将其类型转换为适当的类，然后对其进行修改并返回。
In case you plan to return a completely different object altogether, then that would result in ClassCastException, unless the actual returned object is a subclass of the return type.
如果您计划完全返回一个完全不同的对象，那么这将导致 ClassCastException，除非实际返回的对象是返回类型的子类。
