java技术——Spring Aop

AOP（Aspect Orient Programming），也就是面向切面编程。可以这样理解，面向对象编程（OOP）是从静态角度考虑程序结构，面向切面编程（AOP）是从动态角度考虑程序运行过程。

AOP原理图

下面是一个spring aop的零配置的例子（用maven构建）。

配置文件

Source code

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-3.0.xsd
 
 
http://www.springframework.org/schema/context
 
 
http://www.springframework.org/schema/context/spring-context-3.0.xsd
 
 
http://www.springframework.org/schema/aop
 
 http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
	
	<context:component-scan base-package="com.bobohe">
		<context:include-filter type="annotation"
			expression="org.aspectj.lang.annotation.Aspect" />
	context:component-scan>
	
	<aop:aspectj-autoproxy />
beans>

 

目标对象类

Source code

package com.bobohe.test01;
 
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
 
import javax.annotation.Resource;
 
/**
 * Hello world!
 *
 */
 
@Component("app")
public class App implements AppInterface
{
	public void testAspectJ(String param){
		System.out.println("do test AspectJ:" + param);
	}
}

目标对象接口

Source code

package com.bobohe.test01;
 
public interface AppInterface {
	public void testAspectJ(String param);
}

junit测试类

Source code

package com.bobohe.test01;
 
import com.bobohe.test01.App;
 
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
 
/**
 * Unit test for simple App.
 */
public class AppTest extends TestCase {
 
	public void testApp() {
		BeanFactory bf = new ClassPathXmlApplicationContext("ApplicationContext.xml");
		AppInterface at = (AppInterface) bf.getBean("app");
		at.testAspectJ("real params");
		System.out.println(at.getClass());
		assertTrue(true);
	}
 
}

pom.xml

Source code

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0modelVersion>
 
	<groupId>com.bobohegroupId>
	<artifactId>springtestartifactId>
	<version>0.0.1-SNAPSHOTversion>
	<packaging>jarpackaging>
 
	<name>springtestname>
	<url>http://maven.apache.org
 
	<properties>
		<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
	properties>
 
	<dependencies>
		<dependency>
			<groupId>junitgroupId>
			<artifactId>junitartifactId>
			<version>3.8.1version>
			<scope>testscope>
		dependency>
 
		<dependency>
			<groupId>org.springframeworkgroupId>
			<artifactId>spring-contextartifactId>
			<version>4.1.4.RELEASEversion>
			<scope>runtimescope>
		dependency>
 
		<dependency>
			<groupId>javaxgroupId>
			<artifactId>javaee-apiartifactId>
			<version>6.0version>
		dependency>
 
		<dependency>
			<groupId>org.aspectjgroupId>
			<artifactId>aspectjrtartifactId>
			<version>1.8.3version>
		dependency>
		<dependency>
			<groupId>org.aspectjgroupId>
			<artifactId>aspectjweaverartifactId>
			<version>1.8.3version>
			<scope>runtimescope>
		dependency>
 
	dependencies>
 
 
project>

输出结果

Source code

执行目标方法之前，模拟开始事务 ...
do test AspectJ:被改变的参数
执行目标方法之后，模拟结束事务 ...
class sun.proxy.$Proxy8

从输出结果看，在这个例子中spring用的jdk的动态代理来创建aop代理的。但是当我们的被代理的对象类没有继承接口是，spring会使用cglib来生成aop代理。这一层是spring帮我们处理的。spring会根据实际情况自动切换。

实例代码下载地址：http://pan.baidu.com/s/1sjHO7mP