@Component@Aspectpublic class AopAspect {@Pointcut(value = "execution(* com.ztryou.service.PersonServiceImpl.*(..))")public void pointcut() {}@Before("pointcut()")public void beforeAdvice(JoinPoint point) throws Exception {System.out.println("befor");}@Around(value = "pointcut()")public Object aroundAdvice(ProceedingJoinPoint pjp) {Object obj = null;try {System.out.println("around before");MethodSignature ms = (MethodSignature) pjp.getSignature();Object target = pjp.getTarget();Method method = ms.getMethod();method.invoke(target, 1);obj = pjp.proceed();System.out.println("around after");} catch (Throwable e) {e.printStackTrace();}return obj;}@AfterReturning(value = "pointcut()", returning = "ret")public void afterReturningAdvice(Object ret) {System.out.println("after return");}@AfterThrowing(value = "pointcut()", throwing = "ex")public void afterThrowingAdvice(Exception ex) {System.out.println("after Throw");}@After("pointcut()")public void afterFinallyAdvice() {System.out.println("after");}}
SpringAOP的底层实现主要设计三个方面：
advisor：切面,切面则包含下面的切点和拦截器public interface Advisor {Advice getAdvice();。。。。。}public interface PointcutAdvisor extends Advisor {Pointcut getPointcut();}
pointcut： 切点public interface Pointcut {// 用来匹配类ClassFilter getClassFilter();// 更细粒度的匹配，匹配方法MethodMatcher getMethodMatcher();}
advice：增强（拦截器，用于执行自己的逻辑）public interface Advice {}
这里注意，增强只是一个标识接口，用来表示这是一个增强类。我们要增强的逻辑是要实现MethodInterceptor接口，在invoke方法中写的。
public interface MethodInterceptor extends Interceptor {Object invoke(MethodInvocation invocation) throws Throwable;}
每个都有自己的接口，只需要自己实现子类。
Spring提供的现成的类RegexpMethodPointcutAdvisor类：通过解析正则表达式匹配目标方法。当然它的内部是使用的正则表达式的节点类：JdkRegexpMethodPointcut，开发这直接编写自己的拦截器就好。
使用：
DefaultPointcutAdvisor这个类只是一个切面类，需要自己定义切点和增强。默认的切点是匹配所有的类，如果这样符合预期，那么只需要定义增强类。
增强的拦截增强的逻辑是放在拦截器中执行的：
public class DebugInterceptor implements MethodInterceptor {// MethodInvocation 是一个拦截器执行链，调用proceed()会执行下一个拦截器。// 所以可以在proceed()前后执行自己的逻辑。 public Object invoke(MethodInvocation invocation) throws Throwable { System.out.println("Before: invocation=[" + invocation + "]"); Object rval = invocation.proceed(); System.out.println("Invocation returned"); return rval; }}
使用ProxyFactoryBean创建代理一般创建代码的时候，spring通过bean的postBeanProcessor处理器，对bean进行拦截，创建代理。还有一种方法就是通过ProxyFactoryBean创建代理，但是这种方式只能对一个bean进行代理。例子可以看：TransactionProxyFactoryBean
使用spring aop自己创建代理ProxyFactory factory = new ProxyFactory(myBusinessInterfaceImpl);factory.addAdvice(myMethodInterceptor);factory.addAdvisor(myAdvisor);MyBusinessInterface tb = (MyBusinessInterface) factory.getProxy();
自动代理之前介绍的都是代理一个指定类。那么spring是如何代理容器的类呢？使用的是beanPostProcessor处理器。在初始化后方法中，找到所有切面类，对该bean进行匹配。如果符合，就代理。
包装代理对象org.springframework.aop.framework.Advised接口实现了可以对代理对象的所有操作。
Advisor[] getAdvisors();void addAdvice(Advice advice) throws AopConfigException;void addAdvice(int pos, Advice advice) throws AopConfigException;void addAdvisor(Advisor advisor) throws AopConfigException;void addAdvisor(int pos, Advisor advisor) throws AopConfigException;int indexOf(Advisor advisor);boolean removeAdvisor(Advisor advisor) throws AopConfigException;void removeAdvisor(int index) throws AopConfigException;boolean replaceAdvisor(Advisor a, Advisor b) throws AopConfigException;boolean isFrozen();
封装之后可以进行调节：
Advised advised = (Advised) myObject;Advisor[] advisors = advised.getAdvisors();int oldAdvisorCount = advisors.length;System.out.println(oldAdvisorCount + " advisors");// Add an advice like an interceptor without a pointcut// Will match all proxied methods// Can use for interceptors, before, after returning or throws adviceadvised.addAdvice(new DebugInterceptor());// Add selective advice using a pointcutadvised.addAdvisor(new DefaultPointcutAdvisor(mySpecialPointcut, myAdvice));assertEquals("Added two advisors", oldAdvisorCount + 2, advised.getAdvisors().length);