Spring is based on the annotation @ AspectJ AOP, spring @ aspectjaop

Spring is based on the annotation @ AspectJ AOP, spring @ aspectjaop

In addition to configuring AOP in XML, Spring also supports annotation: Use the @ AspectJ style aspect declaration.

However, the @ AspectJ support needs to be enabled in XML in Annotation mode.<Aop: aspectj-autoproxy/>,An AnnotationAwareAspectJAutoProxyCreator class will be created in the Spring context, and it will automatically proxy some beans. The Bean methods must match the cut points defined in Bena using the @ Aspect annotation, the cut points are defined using the @ Pointcut annotation. Let's take a look at the example below (PS: none of my examples contain parameters ):

The declared entry point @ AspectJ is implemented using the @ Pointcut method under the org. aspectj. lang. annotation package (the method must be of the void type returned. @ Pointcut (value = "Pointcut expression", argNames = "Parameter Name List ")
Public void pointcutName (......) {}
Declaration notification

Pre-notification

Use the @ Before annotation declaration under the org. aspectj. lang. annotation package;
@ Before (value = "entry point expression or naming entry point", argNames = "parameter list parameter name ")

Post-return notification

Use the @ AfterReturning annotation declaration under the org. aspectj. lang. annotation package;
@ AfterReturning (
Value = "entry point expression or named entry point ",
Pointcut = "pointcut expressions or named pointcut ",
ArgNames = "parameter list parameter name ",
Returning = "Response Parameter Name ")

Post-final notification

Use the @ After annotation declaration under the org. aspectj. lang. annotation package;
@ After (
Value = "entry point expression or named entry point ",
ArgNames = "parameter list parameter name ")

Post-exception notificationUse the @ AfterThrowing annotation declaration under the org. aspectj. lang. annotation package
@ AfterThrowing (
Value = "entry point expression or named entry point ",
Pointcut = "pointcut expressions or named pointcut ",
ArgNames = "parameter list parameter name ",
Throwing = "exception parameter name ")

package cn.com.ztz.spring.service;    public interface ShowService {      public void show();  } 

Package cn.com. ztz. spring. service; public class ShowServiceImpl implements ShowService {@ Override public void show () {showBefore (); // showError (); // exception test (post-exception notification) showEnd ();} public void showBefore () {System. out. println ("showBefore ==============");} public void showError () {System. out. println ("showError =============="); throw new RuntimeException ();} public void showEnd () {System. out. println ("showEnd ==================== ");}}

Package cn.com. ztz. spring. service; import org. aspectj. lang. annotation. afterReturning; import org. aspectj. lang. annotation. afterThrowing; import org. aspectj. lang. annotation. aspect; import org. aspectj. lang. annotation. before; import org. aspectj. lang. annotation. pointcut; @ Aspectpublic class AudienceAspect {// defines the cut point @ Pointcut ("execution (* cn.com. ztz. spring. service. showServiceImpl. show (..)) ") public void performance () {// the content of this method is not important. The method itself is only an identifier, @ Pointcut annotation attachment} // pre-notification @ Before ("performance ()") public void taskSeats () {System. out. println ("pending program start =");} // post notification @ After ("performance ()") public void applaud () {System. out. println ("applaud ==========");} // post exception notification @ AfterThrowing ("performance ()") public void demandRefund () {System. out. println ("refund departure ==== ");}}

<! -- Enable @ AspectJ support --> <aop: aspectj-autoproxy/> <bean id = "show" class = "cn.com. ztz. spring. service. showServiceImpl "/> <bean id =" audienceAspect "class =" cn.com. ztz. spring. service. audienceAspect "/>

public static void main(String[] args) {ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");            ShowService hs = ctx.getBean("show", ShowService.class);            System.out.println("======================================");          hs.show();         System.out.println("======================================"); }

Run the test method console output:

==============================================
Waiting for program start =
ShowBefore ================
ShowEnd ======================
Applaud ==========
==============================================

Annotation surround notification

Like Spring's XML-based AOP, the use of @ AspectJ annotations not only limits and defines the pre-and post-notification types. We can also create a surround notification, which requires @ Around.

@ Around (
Value = "entry point expression or named entry point ",
ArgNames = "parameter list parameter name ")

public interface ShowService {      public void show(String param);  }

@Override      public void show(String param) {    System.out.println("around==========="+param);     } 

@ Aspectpublic class AudienceAspect {// defines the cut point @ Pointcut ("execution (* cn.com. ztz. spring. service. showServiceImpl. show (..)) ") public void performance () {// the content of this method is not important. the method itself is only an identifier for @ Pointcut annotation attachment} @ Around (" performance ()") public Object aroundAdvice (ProceedingJoinPoint pjp) throws Throwable {System. out. println ("around before advice =========="); Object retVal = pjp. proceed (new Object [] {"around"}); System. out. println ("around after advice ============"); return retVal ;}}

Run the test method console output:

==============================================
Around before advice ==============
Around = around
Around after advice ==============
==============================================

Introduction@ DeclareParents declaration in the org. AspectJ. lang. annotation package

@ DeclareParents (
Value = "AspectJ syntax type expression ",
DefaultImpl = "Default implementation class of the introduced interface ") 

package cn.com.ztz.spring.service;public interface DeclareService {      public void declare();  }

package cn.com.ztz.spring.service;public class DeclareServiceImpl implements DeclareService {      @Override      public void declare() {          System.out.println("declare=====================");      }  } 

package cn.com.ztz.spring.service;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.DeclareParents;@Aspectpublic class AudienceAspect {@DeclareParents(value="cn.com.ztz.spring.service.ShowServiceImpl+",defaultImpl=cn.com.ztz.spring.service.DeclareServiceImpl.class)private DeclareService declareService;}

public static void main(String[] args) {ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");    DeclareService hs = ctx.getBean("show", DeclareService.class);            System.out.println("======================================");          hs.declare();         System.out.println("======================================"); }

Output result of Running Test method:

==============================================
Declare ==================================
==============================================

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