Around
是一种通知类型,可以确保方法执行前后的通知运行。 以下是Around
通知的语法:
<aop:config> <aop:aspect id="log" ref="logging"> <aop:pointcut id="pointcut-id" expression="execution( expression )"/> <aop:around pointcut-ref="pointcut-id" method="methodName"/> </aop:aspect> </aop:config>
在上面配置中,
pointcut-id
- 切入点的id。methodName
- 在调用函数之前调用的函数的方法名称。要了解上述与周围通知(Around Advice)相关的概念,写一个在实现周围通知(Around Advice)的示例。为了简单,可直接复制之前上一篇文章中的例子,打开并使用Eclipse IDE,并按照以下步骤创建一个Spring应用程序:
Student
项目。bean
配置并运行应用程序,如下所述。整个项目的目录结构如下所示 -
下面是Logging.java
文件的内容。 这实际上是一个Aspect
模块的样本,它定义了在各个点被调用的方法。
package com.zyiz; import org.aspectj.lang.ProceedingJoinPoint; public class Logging { /** * This is the method which I would like to execute * around a selected method execution. */ public String aroundAdvice(ProceedingJoinPoint jp) throws Throwable{ System.out.println("【In Around advice】"); Object[] args=jp.getArgs(); if(args.length>0){ System.out.print("Arguments passed: " ); for (int i = 0; i < args.length; i++) { System.out.print("arg "+(i+1)+": "+args[i]); } } Object result=jp.proceed(args); System.out.println("Returning :" + result); return result.toString(); } }
以下是Student.java文件的内容:
package com.zyiz; 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 ); System.out.println("Exception raised"); throw new IllegalArgumentException(); 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
文件的内容:
package com.zyiz; 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.getName(); } }
以下是配置文件Beans.xml文件的内容:
<?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:config> <aop:aspect id="log" ref="logging"> <aop:pointcut id="selectName" expression="execution(* com.zyiz.Student.getName(..))"/> <aop:around pointcut-ref="selectName" method="aroundAdvice"/> </aop:aspect> </aop:config> <!-- Definition for student bean --> <bean id="student" class="com.zyiz.Student"> <property name="name" value="maxsu" /> <property name="age" value="26"/> </bean> <!-- Definition for logging aspect --> <bean id="logging" class="com.zyiz.Logging"/> </beans>
完成创建源代码和配置文件后,运行应用程序。右键单击应用程序中的MainApp.java
,并使用运行方式作为Java应用程序命令。 如果您的应用程序一切正常,这将打印以下消息:
【In Around advice】 Name : maxsu Returning :maxsu