//Create object to be proxied
Student student = new Student();
//Create the Proxy Factory
AspectJProxyFactory proxyFactory = new AspectJProxyFactory(student);
//Add Aspect class to the factory
proxyFactory.addAspect(Logging.class);
//Get the proxy object
Student proxyStudent = proxyFactory.getProxy();
//Invoke the proxied method.
proxyStudent.getAge();

在上面的語法示例中 -

AspectJProxyFactory - 用于創(chuàng)建代理對象的工廠類。
Logging.class - 包含通知的方面類
Student - 將被通知的業(yè)務(wù)類。

要了解上面提到與代理相關(guān)的概念，我們寫一個(gè)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(gè)Spring應(yīng)用程序：

更新在Spring AOP應(yīng)用實(shí)例中創(chuàng)建過的Student項(xiàng)目。
更新bean配置并運(yùn)行應(yīng)用程序，如下所述。

整個(gè)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(gè)Aspect模塊的樣本，它定義了在各個(gè)點(diǎn)被調(diào)用的方法。

package com.yiibai;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.annotation.Before;

@Aspect
public class Logging {

   /** Following is the definition for a pointcut to select
    *  all the methods available. So advice will be called
    *  for all the methods.
    */
   @Pointcut("execution(* com.yiibai.Student.getAge(..))")
   private void selectGetAge(){}

   /** 
    * This is the method which I would like to execute
    * before a selected method execution.
    */
   @Before("selectGetAge()")
   public void beforeAdvice(){
      System.out.println("[beforeAdvice] Going to setup student profile.");
   }  
}

以下是Student.java文件的內(nèi)容：

package com.yiibai;

public class Student {
   private Integer age;

   public void setAge(Integer age) {
      this.age = age;
   }
   public Integer getAge() {
      System.out.println("Age : " + age );
      return age;
   }   
}

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;
import org.springframework.aop.aspectj.annotation.AspectJProxyFactory;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
             new ClassPathXmlApplicationContext("Beans.xml");

      Student student = (Student) context.getBean("student");

      //Create the Proxy Factory
      AspectJProxyFactory proxyFactory = new AspectJProxyFactory(student);

      //Add Aspect class to the factory
      proxyFactory.addAspect(Logging.class);

      //Get the proxy object
      Student proxyStudent = proxyFactory.getProxy();

      //Invoke the proxied method.
      proxyStudent.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 ">

   <!-- Definition for student bean -->
   <bean id="student" class="com.yiibai.Student">
      <property name="age"  value="26"/>      
   </bean>

   <!-- Definition for logging aspect -->
   <bean id="logging" class="com.yiibai.Logging"/> 

</beans>

運(yùn)行項(xiàng)目

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：

[beforeAdvice] Going to setup student profile.
Age : 26

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