Spring In Action读书笔记之五------------------AOP的参数传递

在AOP方法拦截的时候，总会有一些参数的传递，我们可能希望在调用某个方法的时候，将这些方法悄悄的传递给

暗中的拦截方法，这样的功能如何实现呢，下面我们就这个参数传递的例子来进行一个案例。

首先书写一个接口，这个是暗中的拦截方法执行的接口

package com.bird.springidol;

public interface MindReader {
	public void interceptThoughts(String thoughts);
	public String getThought();
}

然后是他的实现类

package com.bird.springidol;

public class Magician implements MindReader {
	private String thoughts;

	@Override
	public void interceptThoughts(String thoughts) {
		System.out.println("Intercepting volunteer's thoughts");
		this.thoughts = thoughts;
		getThought();
	}

	@Override
	public String getThought() {
		// TODO Auto-generated method stub
		System.out.println("daw"+thoughts);
		return thoughts;
	}

}

然后下面是需要拦截的方法的接口

package com.bird.springidol;

public interface Thinker {
	public void thinkOfSomething(String thoughts);
	public String getThoughts();
}

然后是实现类

package com.bird.springidol;

public class Volunteer implements Thinker {
	private String thoughts;

	@Override
	public void thinkOfSomething(String thoughts) {
		this.thoughts=thoughts;
	}
	
	public String getThoughts(){
		return thoughts;
	}

}

接着就是配置了

<aop:config>
    	<aop:aspect ref="magician">
    		<aop:pointcut id="thinking"
    		expression="execution(* com.bird.springidol.Thinker.thinkOfSomething(String)) and args(thoughts)"/>
    		
    	<aop:before method="interceptThoughts" pointcut-ref="thinking" arg-names="thoughts"/>
    	
    	</aop:aspect>
    </aop:config>

这个配置的意思就是，拦截这个Thinker接口的实现方法，其中的参数命名为thoughts，下面的before方法里面的

interceptThoughts方法接受一个参数，这个参数映射到thoughts这个地方，然后暗中的拦截方法就能接受到参数了。

其实感觉挺扰人的，得好好想想做做例子就会了。

我的测试例子

@Test
	public void test10(){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		Thinker ju = (Thinker) ctx.getBean("volunteer");
		ju.thinkOfSomething("Queen of Hearts");
		
	}

运行结果为

2012-5-22 12:25:05 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@167d940: startup date [Tue May 22 12:25:05 CST 2012]; root of context hierarchy
2012-5-22 12:25:05 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [beans.xml]
2012-5-22 12:25:05 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@ef137d: defining beans [org.springframework.aop.config.internalAutoProxyCreator,duke,duke1,sonnet29,poeticDuke,theStage,saxophone,guitar,kenny,hank,hank1,car1,audience,perform,magician,volunteer,org.springframework.aop.aspectj.AspectJPointcutAdvisor#0,org.springframework.aop.aspectj.AspectJPointcutAdvisor#1,org.springframework.aop.aspectj.AspectJPointcutAdvisor#2,org.springframework.aop.aspectj.AspectJPointcutAdvisor#3,performance,org.springframework.aop.aspectj.AspectJPointcutAdvisor#4,thinking]; root of factory hierarchy
Intercepting volunteer's thoughts
dawQueen of Hearts