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SpringAOP

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时间： 2017/5/4 17:05:39
参考：Spring Aop

concepts and terminology 概念和术语#

  • Aspect：
  • Join point:
  • Advice：
  • Before advice
  • After returning advice
  • After throwing advice
  • After (finally) advice
  • Around advice
  • Pointcut：
  • Introduction：
  • Target object:
  • AOP proxy：JDK dynamic proxy or a CGLIB proxy。
  • Weaving：

使用#

  1. 配置 @AspectJ可用

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    @Configuration
@EnableAspectJAutoProxy
public class AppConfig {

}

  2. Declaring an aspect

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    @Component
@Aspect
public class NotVeryUsefulAspect {

}

    1. Declaring a pointcut

      @Pointcut("execution(* transfer(..))")// the pointcut expression private void anyOldTransfer() {}// the pointcut signature 4. Supported Pointcut Designators

    2. execution - for matching method execution join points, this is the primary pointcut designator you will use when working with Spring AOP

    3. within - limits matching to join points within certain types (simply the execution of a method declared within a matching type when using Spring AOP)
    4. this - limits matching to join points (the execution of methods when using Spring AOP) where the bean reference (Spring AOP proxy) is an instance of the given type
    5. target - limits matching to join points (the execution of methods when using Spring AOP) where the target object (application object being proxied) is an instance of the given type
    6. args - limits matching to join points (the execution of methods when using Spring AOP) where the arguments are instances of the given types
    7. @target - limits matching to join points (the execution of methods when using Spring AOP) where the class of the executing object has an annotation of the given type
    8. @args - limits matching to join points (the execution of methods when using Spring AOP) where the runtime type of the actual arguments passed have annotations of the given type(s)
    9. @within - limits matching to join points within types that have the given annotation (the execution of methods declared in types with the given annotation when using Spring AOP)
    10. @annotation - limits matching to join points where the subject of the join point (method being executed in Spring AOP) has the given annotation

  3. Combining pointcut expressions
    pointcuts 可见性与private，protected，public有关，和Java类相似。

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    @Pointcut("execution(public * *(..))")
private void anyPublicOperation() {}

@Pointcut("within(com.xyz.someapp.trading..*)")
private void inTrading() {}

@Pointcut("anyPublicOperation() && inTrading()")
private void tradingOperation() {}

    1. Sharing common pointcut definitions

      @Aspect public class SystemArchitecture {

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      @Pointcut("within(com.xyz.someapp.web..*)")
public void inWebLayer() {}

@Pointcut("within(com.xyz.someapp.service..*)")
public void inServiceLayer() {}

@Pointcut("within(com.xyz.someapp.dao..*)")
public void inDataAccessLayer() {}

@Pointcut("execution(* com.xyz.someapp..service.*.*(..))")
public void businessService() {}

@Pointcut("execution(* com.xyz.someapp.dao.*.*(..))")
public void dataAccessOperation() {}

      }

  4. Declaring advice

  5. Before advice

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        @Aspect
    public class BeforeExample {

        @Before("com.xyz.myapp.SystemArchitecture.dataAccessOperation()")
        public void doAccessCheck() {
            // ...
        }

    }
    • After returning advice
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      @Aspect
public class AfterReturningExample {

    @AfterReturning("com.xyz.myapp.SystemArchitecture.dataAccessOperation()")
    public void doAccessCheck() {
        // ...
    }

}

//获取返回值
@Aspect
public class AfterReturningExample {

    @AfterReturning(
        pointcut="com.xyz.myapp.SystemArchitecture.dataAccessOperation()",
        returning="retVal")
    public void doAccessCheck(Object retVal) {
        // ...
    }

}

  6. After throwing advice

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        @Aspect
    public class AfterThrowingExample {

        @AfterThrowing("com.xyz.myapp.SystemArchitecture.dataAccessOperation()")
        public void doRecoveryActions() {
            // ...
        }

    }

  7. After (finally) advice

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        @Aspect
    public class AfterFinallyExample {

        @After("com.xyz.myapp.SystemArchitecture.dataAccessOperation()")
        public void doReleaseLock() {
            // ...
        }

    }

  8. Around advice

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    @Aspect
public class AroundExample {

    @Around("com.xyz.myapp.SystemArchitecture.businessService()")
    public Object doBasicProfiling(ProceedingJoinPoint pjp) throws Throwable {
        // start stopwatch
        Object retVal = pjp.proceed();
        // stop stopwatch
        return retVal;
    }

}