Spring学习心得（二）
1. advice有四种：Before advice ，After advice ，Around advice ,Throws advice
2. 这四种advice分别需要继承的接口为
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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的区别是Before advice是只要没有异常，目标方法一定会被调用，然而Around advice，只有当调用MethodInvocation.proceed()后目标方法才能被调用。而且Around advice还可以返回想返回的值：如Object obj=invocation.proceed();