21Spring re-usable pointcut expression

Look directly at the code:

 package com.cn.spring.aop.impl;  subtraction interface class public  Arithmeticcalculator {int Add (int I, int J); int Sub (int I, int J); int mul (int I, int J); int Div (int I, int j);                 

PackageCom.cn.spring.aop.impl;ImportOrg.springframework.stereotype.Component;//Implementation class@ComponentPublicClass ArithmeticcalculatorimplImplementsArithmeticcalculator {@OverridePublicint Add (int I,Intj) {int result = i +JReturnResult } @OverridePublicint Sub (int I,Intj) {int result = i- J; return result;} @Override public int mul (int I, " Span style= "color: #0000ff;" >int J) {int result = I * J ; return result;} @Override public int Div (int I, " Span style= "color: #0000ff;" >int J) {int result = I/ J ; return      

 PackageCom.cn.spring.aop.impl;ImportOrg.aspectj.lang.JoinPoint;ImportOrg.aspectj.lang.ProceedingJoinPoint;Importorg.aspectj.lang.annotation.*;ImportOrg.springframework.core.annotation.Order;Importorg.springframework.stereotype.Component;Importjava.util.Arrays;Importjava.util.List;//declare this class as a tangent: you first need to put the class in the IOC container, declared as a tangent plane//You can use @order annotations to specify the priority of a slice, the lower the value, the higher the priority@Order (2) @Aspect @component Public classLoggingaspect {/*** Define a method that declares a pointcut expression, which, in general, does not need to be added to other code in the method * use @pointcut to declare other notifications following the pointcut expression * to refer to the current pointcut expression directly using the method name*/@Pointcut (Value= "Execution (public int arithmeticcalculator.* (..))")     Public voiddeclarejoinpointexpression () {}//declares that the method is a pre-notification: Executes before the target method starts@Before ("Declarejoinpointexpression ()")     Public voidBeforemethod (Joinpoint joinpoint) {String methodName=joinpoint.getsignature (). GetName (); List<Object> args =arrays.aslist (Joinpoint.getargs ()); System.out.println ("The method" + MethodName + "begins with" +args); }    //Post notification: Notification of execution after the target method executes (regardless of whether an exception occurs)//The results of the target method execution are not yet accessible in the post notification@After ("Declarejoinpointexpression ()")     Public voidAftermethod (Joinpoint joinpoint) {String methodName=joinpoint.getsignature (). GetName (); List<Object> args =arrays.aslist (Joinpoint.getargs ()); System.out.println ("The method" + MethodName + "ends with" +args); }    /*** Code executed after the normal end of the method * Returns a notification that the return value of the method can be accessed *@paramJoinpoint*/@AfterReturning (Value= "Declarejoinpointexpression ()", returning= "Result")     Public voidafterreturning (joinpoint joinpoint, Object result) {String methodName=joinpoint.getsignature (). GetName (); List<Object> args =arrays.aslist (Joinpoint.getargs ()); System.out.println ("The method ends WITD" +result); }    //code that executes when the target method exception occurs//You can access the exception object, and you can specify that the notification code be executed when a specific exception occurs@AfterThrowing (value = "declarejoinpointexpression ()", throwing= "Ex")     Public voidafterreturning (Joinpoint joinpoint, Exception ex) {String methodName=joinpoint.getsignature (). GetName (); System.out.println ("The method" + MethodName + "Occures exception with:" +ex); }    /*** Surround notifications need to carry Proceedingjoinpoint type parameters * Surround notification is similar to the whole process of dynamic agents: Parameters of the Proceedingjoinpoint type can determine whether the target method is executed * and the surround notification must have a return value, returning Return value is the returned value of the target method *@paramProceedingjoinpoint*/@Around ("Declarejoinpointexpression ()")     PublicObject Aroundmethod (Proceedingjoinpoint proceedingjoinpoint) {object result=NULL; String MethodName=proceedingjoinpoint.getsignature (). GetName (); //Execute target Method        Try {            //front-facing notificationsSystem.out.println ("the method" + MethodName + "begins with" +arrays.aslist (Proceedingjoinpoint.getargs ())); Result=proceedingjoinpoint.proceed (); //Back to NotificationsSystem.out.println ("The method ends with" +result); } Catch(Throwable throwable) {//Exception NotificationSystem.out.println ("the method" + MethodName + "Occures exception with:" +throwable); Throw Newruntimeexception (Throwable); }        //Post NotificationSystem.out.println ("the method" + MethodName + "ends"); returnresult; }}

 PackageCom.cn.spring.aop.impl;ImportOrg.aspectj.lang.JoinPoint;ImportOrg.aspectj.lang.annotation.Aspect;ImportOrg.aspectj.lang.annotation.Before;ImportOrg.springframework.core.annotation.Order;Importorg.springframework.stereotype.Component;Importjava.util.Arrays; @Order (1) @Aspect @component Public classvalidationaspect {@Before ("Loggingaspect.declarejoinpointexpression ()")//reuse tangent expression Public voidValidateargs (Joinpoint joinpoint) {System.out.println ("Validate:" +arrays.aslist (Joinpoint.getargs ())); }}

PackageCom.cn.spring.aop.impl;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext;PublicClassMain {PublicStaticvoidMain (string[] args) {//1. Create a spring IOC container applicationcontext CTX =new Classpathxmlapplicationcontext ("17-1.xml"); //2. Gets the instance of the bean from the IOC container huo arithmeticcalculator arithmeticcalculator = Ctx.getbean (arithmeticcalculator.  Class); //3. Use bean int result = Arithmeticcalculator.add (3, 6); SYSTEM.OUT.PRINTLN ("Result:" + result); //result = Arithmeticcalculator.div (3, 0); // System.out.println ("Result:" + result);} }           

<?XML version= "1.0" encoding= "UTF-8"?><Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"Xmlns:context= "Http://www.springframework.org/schema/context"Xmlns:aop= "HTTP://WWW.SPRINGFRAMEWORK.ORG/SCHEMA/AOP"Xsi:schemalocation= "Http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http ://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http ://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd "> <context:component-scan base-package= "Com.cn.spring.aop.impl"> </  Context:component-scan> <!-- make ASPJECTJ annotations work: Automatically generate proxy objects for matching classes-  <AOP: Aspectj-autoproxy></aop:aspectj-autoproxy></beans>  

21Spring re-usable pointcut expression