@AfterReturning
是一種通知類型,可確保方法執(zhí)行成功后運(yùn)行通知。 以下是@AfterReturning
通知的語法:
語法
@AfterReturning(pointcut="execution(* com.yiibai.Student.*(..))", returning="retVal")
public void afterReturningAdvice(JoinPoint jp, Object retVal){
System.out.println("Method Signature: " + jp.getSignature());
System.out.println("Returning:" + retVal.toString() );
}
在上面的語法示例中 -
@AfterReturning
- 如果方法返回成功,則將函數(shù)標(biāo)記為在切入點(diǎn)覆蓋的方法之前執(zhí)行的通知。@Pointcut
- 將函數(shù)標(biāo)記為切入點(diǎn)@After
- 將函數(shù)標(biāo)記為在切入點(diǎn)覆蓋的方法之后執(zhí)行的通知。execution( expression )
- 涵蓋應(yīng)用通知的方法的表達(dá)式。returning
- 要返回的變量的名稱。要了解上面提到的@AfterReturning Advice
通知相關(guān)的概念,我們寫一個Spring AOP基于注解的應(yīng)用例子,它將使用基于注解配置實(shí)現(xiàn)通知。打開并使用Eclipse IDE,并按照以下步驟創(chuàng)建一個Spring應(yīng)用程序:
Student
項(xiàng)目。bean
配置并運(yùn)行應(yīng)用程序,如下所述。整個項(xiàng)目的目錄結(jié)構(gòu)如下所示 -
下面是Logging.java
文件的內(nèi)容。 這實(shí)際上是一個Aspect
模塊的樣本,它定義了在各個點(diǎn)被調(diào)用的方法。
package com.yiibai;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
@Aspect
public class Logging {
/**
* This is the method which I would like to execute
* after a selected method execution.
*/
@AfterReturning(pointcut="execution(* com.yiibai.Student.*(..))", returning="retVal")
public void afterReturningAdvice(JoinPoint jp, Object retVal){
System.out.println("[afterReturningAdvice] Method Signature: " + jp.getSignature());
System.out.println("[afterReturningAdvice] Returning: " + retVal.toString() );
}
}
以下是Student.java文件的內(nèi)容:
package com.yiibai;
public class Student {
private Integer age;
private String name;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
System.out.println("Age : " + age );
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
System.out.println("Name : " + name );
return name;
}
public void printThrowException(){
System.out.println("Exception raised");
throw new IllegalArgumentException();
}
}
以下是MainApp.java
文件的內(nèi)容:
package com.yiibai;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("Beans.xml");
Student student = (Student) context.getBean("student");
student.getAge();
}
}
以下是配置文件Beans.xml文件的內(nèi)容:
<?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-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">
<aop:aspectj-autoproxy/>
<!-- Definition for student bean -->
<bean id="student" class="com.yiibai.Student">
<property name="name" value="minsu" />
<property name="age" value="26"/>
</bean>
<!-- Definition for logging aspect -->
<bean id="logging" class="com.yiibai.Logging"/>
</beans>
完成創(chuàng)建源代碼和配置文件后,運(yùn)行應(yīng)用程序。右鍵單擊應(yīng)用程序中的MainApp.java
,并使用運(yùn)行方式作為Java應(yīng)用程序命令。 如果您的應(yīng)用程序一切正常,這將打印以下消息:
Age : 24
[afterReturningAdvice] Method Signature: Integer com.yiibai.Student.getAge()
[afterReturningAdvice] Returning: 24