使用Spring Introducation 让Java类实现动态语言特性
当我们没有一个实现类源代码以致不能为实现类增加新的方法时，我们在java语言中往往是无法实现的，但动态语言比（如JS），对动态对象增加可操作的方法是很容易得，我们借助Spring的Introduction这个特殊的advise,同样可以实现动态语言的这个特性
原始的业务接口及实现
packageIntroduction;
publicinterfaceISome...{
publicvoiddoSome();
}
packageIntroduction;
publicclassSomeimplementsISome...{
publicvoiddoSome()...{
System.out.println("原来的方法");
}
}
我们新增的业务接口和实现，其中实现类同时实现了业务接口和SpringIntroduction接口
packageIntroduction;
publicinterfaceIOther...{
publicvoiddoOther();
}
packageIntroduction;
importorg.aopalliance.intercept.MethodInvocation;
importorg.springframework.aop.IntroductionInterceptor;
publicclassOtherimplementsIOther,IntroductionInterceptor...{
publicvoiddoOther()...{
System.out.println("增加的职责");
}
publicObjectinvoke(MethodInvocationmethodInvocation)throwsThrowable...{
if(implementsInterface(methodInvocation.getMethod().getDeclaringClass()))...{
returnmethodInvocation.getMethod().invoke(this,methodInvocation.getArguments());
}else...{
returnmethodInvocation.proceed();
}
}
//判断是否来自与IOther接口的方法调用
publicbooleanimplementsInterface(Classclazz)...{
returnclazz.isAssignableFrom(IOther.class);
}
}
配置文件：
<?xmlversion="1.0"encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
<beanid="some"class="Introduction.Some"/>
<beanid="other"class="Introduction.Other"/>
<beanid="otherAdvisor"class="org.springframework.aop.support.DefaultIntroductionAdvisor">
<constructor-argref="other"></constructor-arg>
<constructor-argvalue="Introduction.IOther"></constructor-arg>
[img]http://b19.photo.store.qq.com/http_imgload.cgi?/rurl4_b=b319ad0568b952709699cf254a19161bed53f2f2894a