<repositories><repository><id>nexus-public</id><url>http://maven.scm.baidu.com:8081/nexus/content/groups/public</url></repository><repository><id>nexus-public-snapshots</id><url>http://maven.scm.baidu.com:8081/nexus/content/groups/public-snapshots</url></repository>
</repositories>

Hello! Jack
---------- Throw Exception ----------
Target Class: aop.demo7.GreetingImpl
Method Name: sayHello
Exception Message: Error
-------------------------------------
Exception in thread "main" java.lang.RuntimeException: Error
......Process finished with exit code 1

@Component
public class GreetingIntroAdvice extends DelegatingIntroductionInterceptor implements Apology {public void saySorry(String name) {System.out.println("Sorry! " + name);}@Overridepublic Object invoke(MethodInvocation invocation) throws Throwable {return super.invoke(invocation);}
}

<bean id="greetingProxy" class="org.springframework.aop.framework.ProxyFactoryBean"><property name="interfaces" value="aop.demo8.Apology"/><property name="target" ref="greetingImpl"/><property name="interceptorNames" value="greetingIntroAdvice"/><property name="proxyTargetClass" value="true"/>
</bean>

<bean id="greetingAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor"><property name="advice" ref="greetingAroundAdvice"/><property name="pattern" value="aop.demo9.GreetingImpl.good.*"/></bean><bean id="greetingProxy" class="org.springframework.aop.framework.ProxyFactoryBean"><property name="target" ref="greetingImpl"/><property name="interceptorNames" value="greetingAdvisor"/><property name="proxyTargetClass" value="true"/></bean>

<bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator"><property name="beanNames" value="*Impl"/><property name="interceptorNames" value="greetingAroundAdvice"/><property name="optimize" value="true"/></bean>

以上使用 BeanNameAutoProxyCreator 只为后缀为“Impl”的 Bean 生成代理。需要注意的是，这个地方我们不能定义代理接口，也就是 interfaces 属性，因为我们根本就不知道这些 Bean 到底实现了多少接口。此时不能代理接口，而只能代理类。所以这里提供了一个新的配置项，它就是 optimize。若为 true 时，则可对代理生成策略进行优化（默认是 false 的）。也就是说，如果该类有接口，就代理接口（使用 JDK 动态代理）；如果没有接口，就代理类（使用 CGLib 动态代理）。而并非像之前使用的 proxyTargetClass 属性那样，强制代理类，而不考虑代理接口的方式。可见 Spring AOP 确实为我们提供了很多很好地服务。

   <bean id="greetingAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor"><property name="pattern" value="aop.demo11.GreetingImpl.good.*"/><property name="advice" ref="greetingAroundAdvice"/></bean><bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator"><property name="optimize" value="true"/></bean>

在 Spring 配置文件中，仍然会存在大量的切面配置。然而在有很多情况下 Spring AOP 所提供的切面类真的不太够用了，比如：想拦截指定注解的方法，我们就必须扩展 DefaultPointcutAdvisor 类，自定义一个切面类，然后在 Spring 配置文件中进行切面配置。不做不知道，做了您就知道相当麻烦了。

@Aspect
@Component
public class GreetingAspect {@Around("execution(* aop.demo12.GreetingImpl.*(..))")public Object around(ProceedingJoinPoint pjp) throws Throwable {before();Object result = pjp.proceed();after();return result;}private void before() {System.out.println("Before");}private void after() {System.out.println("After");}
}

    <context:component-scan base-package="aop.demo"/><aop:aspectj-autoproxy proxy-target-class="true"/>

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Tag {
}

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;@Aspect
@Component
public class GreetingAspect {@Around("@annotation(aop.demo13.Tag)")public Object around(ProceedingJoinPoint pjp) throws Throwable {before();Object result = pjp.proceed();after();return result;}private void before() {System.out.println("Before");}private void after() {System.out.println("After");}
}

@Component
public class GreetingImpl implements Greeting {@Tagpublic void sayHello(String name) {System.out.println("Hello! " + name);}
}

@Aspect
@Component
public class GreetingAspect {@DeclareParents(value = "aop.demo14.GreetingImpl", defaultImpl = ApologyImpl.class)private Apology apology;
}

package aop.demo14;public class ApologyImpl implements Apology {public void saySorry(String name) {System.out.println("Sorry! " + name);}
}

使用 AspectJ 的引入增强比原来的 Spring AOP 的引入增强更加方便了，而且还可面向接口编程（以前只能面向实现类），这也算一个非常巨大的突破。

public class Client {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("aop/demo14/spring.xml");Greeting greeting = (Greeting) context.getBean("greetingImpl");greeting.sayHello("Jack");Apology apology = (Apology) greeting;apology.saySorry("Jack");}
}

package aop;public interface Greeting {void sayHello(String name);
}

    <bean id="greetingImpl" class="aop.demo15.GreetingImpl"/><bean id="greetingAspect" class="aop.demo15.GreetingAspect"/><aop:config><aop:aspect ref="greetingAspect"><aop:around method="around" pointcut="execution(* aop.demo15.GreetingImpl.*(..))"/></aop:aspect></aop:config>