Question

我知道在春天有两种创建代理的方法，一种是使用 JDK代理，另一种是使用 CGLIB 。我也知道这两种代理之间的区别。但我无法理解春天的 AOP 。

例如：

public interface Performance {
    void perform();
}

public class AnotherPerformance implements Performance {

    @Override
    public void perform() {
            System.out.println("AnotherPerformance is performing");
        }
    }
}

方面 -

@Component
@Aspect
public class Audience {

    @Pointcut("execution(* com.xxx.aspect.Performance.perform(..))")
    public void perform(){

    }

    @Before("perform()")
    public void silenceCellphones(){
        System.out.println("silence cell phones");
    }

    @Before("perform()")
    public void takeSeats(){
        System.out.println("Taking seats");
    }

    @AfterReturning("perform()")
    public void applause(){
        System.out.println("CLAP CLAP CLAP!!!!");
    }

    @AfterThrowing("perform()")
    public void demandRefund(){
        System.out.println("Demanding refund!!!!");
    }


    @Around("perform()")
    public void watchPerformance(ProceedingJoinPoint joinPoint){
        try {
            System.out.println("silence cell phones");
            System.out.println("Taking seats");

            joinPoint.proceed();

            System.out.println("CLAP CLAP CLAP!!!!");
        } catch(Throwable e){
            System.out.println("Demanding refund!!!!");
        }
    }
}

客户端代码如下：

public static void main(String[] args) {
    ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-xxx.xml");
    AnotherPerformance performance = ctx.getBean("anotherPerformance",AnotherPerformance.class);
}

从中删除<aop:aspectj-autoproxy proxy-target-class="true"/>时弹簧配置文件，抛出错误：

Exception in thread "main" org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'anotherPerformance' is expected to be of type 'com.aspect.xmlconfig.AnotherPerformance' but was actually of type 'com.sun.proxy.$Proxy2'
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:378)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1084)
    at com.aspect.xmlconfig.AnotherMain.main(AnotherMain.java:22)
20:47:21.028 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Failed to convert bean 'anotherPerformance' to required type 'com.springinaction.aspect.xmlconfig.AnotherPerformance'
org.springframework.beans.ConversionNotSupportedException: Failed to convert value of type 'com.sun.proxy.$Proxy2 implementing com.springinaction.aspect.Performance,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised,org.springframework.core.DecoratingProxy' to required type 'com.aspect.xmlconfig.AnotherPerformance'; nested exception is java.lang.IllegalStateException: Cannot convert value of type 'com.sun.proxy.$Proxy2 implementing com.aspect.Performance,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised,org.springframework.core.DecoratingProxy' to required type 'com.aspect.xmlconfig.AnotherPerformance': no matching editors or conversion strategy found
    at org.springframework.beans.TypeConverterSupport.doConvert(TypeConverterSupport.java:74)
    at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:40)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:371)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1084)
    at com.aspect.xmlconfig.AnotherMain.main(AnotherMain.java:22)

proxy-target-class=true使用 CGLIB 创建代理，但这里的类Perfromance是一个接口，为什么spring无法创建代理对象使用JDK动态代理？

<aop：aspectj-autoproxy proxy-target-class =“true”>如何真正起作用？

0 个答案: