Spring學習心得（二）
1. advice有四種：Before advice ，After advice ，Around advice ,Throws advice
2. 這四種advice分別需要繼承的接口為
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Advice type
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Interface
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Throws advice
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org.aopalliance.intercept.MethodInterceptor
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Before advice
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org.springframework.aop.BeforeAdvice
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After advice
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org.springframework.aop.AfterReturningAdvice
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Throws advice
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org.springframework.aop.ThrowsAdvice
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3．Around advice和Before advice的區別是Before advice是只要沒有異常，目標方法一定會被調用，然而Around advice，只有當調用MethodInvocation.proceed()后目標方法才能被調用。而且Around advice還可以返回想返回的值：如Object obj=invocation.proceed();