[英]Spring AOP proxy use
我嘗試使用AOP
代理在spring框架中為類引入了一種新方法。 但是在控制台上,我看到了class cast exeption
。
I WorkingException in thread "main" java.lang.ClassCastException: com.proxy.$Proxy11 cannot be cast to com.proxy.Spoker
at com.proxy.MyAspect.extendsPosibility(MyAspect.java:27)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:603)
at org.springframework.aop.aspectj.AspectJMethodBeforeAdvice.before(AspectJMethodBeforeAdvice.java:39)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:49)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at com.proxy.$Proxy11.perform(Unknown Source)
at com.proxy.TestAOP.main(TestAOP.java:15)
我有課
public class TestAOP {
/**
* @param args
*/
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
Performer per = (Performer) context.getBean("guitar");
per.perform();
}
}
@Component
@Qualifier("guitar")
public class Guitar implements Performer{
@Override
public void perform() {
System.out.println("I PLAY");
}
}
方面
@Aspect
@Component
public class MyAspect {
@DeclareParents(defaultImpl = Guitar.class, value = "*.SpookerImp")
@Autowired
@Qualifier("guitar")
private Performer guitar;
@Before("performAll()")
public void extendsPosibility() {
System.out.println("I Working");
((Spoker)guitar).spook();
}
@Pointcut("execution(* *.*())")
public void performAll() {
}
}
@Component("SpokerImp")
class SpookerImp implements Spoker {
@Override
public void spook() {
System.out.println("I Spoke");
}
}
接口
interface Performer{
void perform();
}
interface Spoker {
void spook();
}
和Beans.xml
配置文件。
<?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"
xmlns:context="http://www.springframework.org/schema/context"
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
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
<context:annotation-config></context:annotation-config>
<context:component-scan base-package="com.proxy"></context:component-scan>
</beans>
我認為您的解決方法有誤,我嘗試了以下方法,它的工作原理是:
@Aspect
@Component
public class MyAspect {
@DeclareParents(defaultImpl = Guitar.class, value = "com.proxy.SpookerImp")
private Performer guitar;
}
和測試與此:
Spoker spoker = (Spoker)context.getBean("SpokerImp");
spoker.spook();
((Performer)spoker).perform();
如上所示,我正在將spoker
投給Performer
。 這就是DeclareParents所表示的,對於SpokerImpl
(值一個)的實現,將Performer
聲明為Guitar
的實現的父項。
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