Basic AOP knowledge and annotation method and xml configuration method for AOP aspect Programming

<Span style = "font-family:; font-size: 10.5pt; letter-Spacing: 0pt;"> AOP concept </span>

Aspect (aspect): it is similar to a class, but the focus of the two is different. The class is the abstraction of Object Features, while the aspect is the abstraction of cross-cutting concerns.

Joinpoint: the so-called connection point is the intercepted point. In spring, these points are methods, because spring only supports connection points of the method type, in fact, joinpoint can also be a field or class constructor.

Pointcut: defines the points to intercept.

Advice (notification): After the intercepted joinpoint, the task is to notify. Notifications are divided into pre-notification, post-notification, exception notification, final notification, and surround notification. Notifications are what to do.

Target: the target object of the proxy.

Weave: it refers to the process of applying the aspect to the target object and causing the proxy object to be created.

Introduction (introduced); without modifying the class code, introduction can dynamically add some methods or fields at runtime.

Jar packages used by AOP

Spring. Jar

Commons-logging.jar

Aspectjweaver. Jar

Aspectjrt. Jar

Cglib-nodep-2.1.3.jar

If the sr250 annotation is used, such as @ resource/@ postconstruct/@ predestroy, The common-annotation.jar is also introduced.

Configuration of the AOP namespace

Use Spring framework AOP to introduce the following AOP namespace (red part)

<? XML version = "1.0" encoding = "UTF-8"?>

<Beans xmlns = "http://www.springframework.org/schema/beans"

Xmlns: xsi = "http://www.w3.org/2001/XMLSchema-instance"

Xmlns: AOP = "http://www.springframework.org/schema/aop"

Xsi: schemalocation = "http://www.springframework.org/schema/beans

Http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

Http://www.springframework.org/schema/aop

Http://www.springframework.org/schema/aop/spring-aop-2.5.xsd>

<AOP: aspectj-autoproxy/>

</Beans>

The following is the main code of the sample of AOP aspect programming using the annotation method.

Package COM. gdhdcy. service; import Org. aspectj. lang. proceedingjoinpoint; import Org. aspectj. lang. annotation. after; import Org. aspectj. lang. annotation. afterreturning; import Org. aspectj. lang. annotation. afterthrowing; import Org. aspectj. lang. annotation. around; import Org. aspectj. lang. annotation. aspect; import Org. aspectj. lang. annotation. before; import Org. aspectj. lang. annotation. pointcut; @ aspectpublic class myinterceptor {@ pointcut ("execution (* COM. gdhdcy. service. impl. personservicebean. *(..)) ") Private void anymethod () {}; // life start point @ before (" anymethod () & ARGs (name) ") // enter the name of the Start method, remember to add () Public void doaccesscheck (string name) {system. out. println ("pre-notification" + name);} // @ afterreturning ("anymethod ()") @ afterreturning (pointcut = "anymethod ()", returning = "result ") // obtain the return value public void doafterreturning (string result) {system. out. println ("post notification" + result) ;}@ after ("anymethod ()") Public void doafter () {system. out. println ("final notification");} // @ afterthrowing ("anymethod ()") @ afterthrowing (pointcut = "anymethod ()", throwing = "e ") public void doafterthrowing (exception e) {system. out. println ("exception notification" + E) ;}@ around ("anymethod ()") Public object doaround (proceedingjoinpoint pjp) throws throwable {system. out. println ("surround notification entry"); object result = pjp. proceed (); system. out. println ("surround notification exit"); return result ;}}

Annotation method beans. xml configuration document

<? XML version = "1.0" encoding = "UTF-8"?> <Beans xmlns = "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-2.5.xsd http://www.springframework.org/schema/conte XT http://www.springframework.org/schema/context/spring-context-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd "> <AOP: aspectj-autoproxy/> <! -- Based on Annotation --> <bean id = "myinterceptor" class = "com. gdhdcy. service. myinterceptor "/> <bean id =" personservice "class =" com. gdhdcy. service. impl. personservicebean "/> </beans>

Source code link:

Http://pan.baidu.com/s/1jGmQMjG

Main Code of the XML method AOP aspect programming example

Package CN. itcast. service; import Org. aspectj. lang. proceedingjoinpoint;/*** aspect **/public class myinterceptor {public void doaccesscheck () {system. out. println ("pre-notification");} public void doafterreturning () {system. out. println ("post notification");} public void doafter () {system. out. println ("final notification");} public void doafterthrowing () {system. out. println ("exception notification");} public object dobasicprofiling (proceedingjoinpoint pjp) throws throwable {system. out. println ("access method"); object result = pjp. proceed (); system. out. println ("Exit method"); return result ;}}

Xml configuration document

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="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-2.5.xsd           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">        <aop:aspectj-autoproxy/>         <bean id="personService" class="com.gdhdcy.service.impl.PersonServiceBean"></bean>        <bean id="aspetbean" class="com.gdhdcy.service.MyInterceptor"/>        <aop:config>        <aop:aspect id="asp" ref="aspetbean">        <aop:pointcut id="mycut" expression="execution(* com.gdhdcy.service..*.*(..))"/>        <aop:before pointcut-ref="mycut" method="doAccessCheck"/>        <aop:after-returning pointcut-ref="mycut" method="doAfterReturning"/>  <aop:after-throwing pointcut-ref="mycut" method="doAfterThrowing"/>  <aop:after pointcut-ref="mycut" method="doAfter"/>  <aop:around pointcut-ref="mycut" method="doBasicProfiling"/>        </aop:aspect>        </aop:config></beans>