SpringAOP

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

   @Configuration
   @EnableAspectJAutoProxy
   public class AppConfig {
   
   }
   

2. Declaring an aspect

   @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。

   @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 {

      @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

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

   • After returning advice

     @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

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

7. After (finally) advice

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

8. Around advice

   @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;
       }
   
   }