spring 笔记 (3)-aop
1.前置通知
public interface MethodBeforeAdvice{
??? void before(Method method, Object[] args,Object target)throws Throwable;
}
public class WelcomeAdvice implements MethodBeforeAdvice{
??? public void before(Method method, Object[] args, Object target){
??? ??? Customer customer =(Customer) args[0];
??? ??? System.out.println("Hello "+customer.getName() +" .How are you doing?");
??? }
}
<beans>
??? <bean id="**Target" class="org.springframework.aop.framework.ProxyFactoryBean">
??? ??? <property name="proxyInterfaces">
??? ??? ??? <value>interface of the target class</value>
??? ??? </property>
??? ??? <property name="interceptorNames">
??? ??? ??? <list>
??? ??? ??? ??? <value>welcomeAdvice</value>
??? ??? ??? </list>
??? ??? </property>
??? ??? <property name="target">
??? ??? ??? <ref bean="**Target"/>
??? ??? </property>
??? </bean>
</beans>
?
public interface AfterReturningAdvice{
??? void afterReturning(Object returnValue,Method method, Object[] args,Object target)throws Throwable;
}
public class ThankYouAdvice implements AfterReturningAdvice{
??? public void afterReturning(Object returnValue, Method method, Object[] arg2,Object target)throws Throwable{
??? ??? System.out.println("Thank you.");
??? }
}
public interface MethodInterceptor extends Interceptor{
??? Object invoke(MethodInvocation invocation)throws Throwable;
}
MethodInterceptor 接口和前面的2种通知不同:它可以控制目标方法是否真的被调用.
通过调用MethodInvocation.proceed()方法来调用.而且,MethodInterceptor可以控制返回的对象.
你可以返回一个与proceed()方法返回对象完全不同的对象.
