Spring之AOP

之前在另外一篇博文里介绍过AOP的概念, 这边不在赘述, 可以参考 AOP与动态代理

本文主要介绍Spring中AOP的应用.

切入点: 具体实现类的方法

连接点: 接口中的方法

 

Advice

---

• 前置MethodBeforeAdvice
• 后置AfterReturnAdvice
• 环绕MethodInterceptor
• ThrowsAdvice

public class MyServiceBeforeAdvice implements MethodBeforeAdvice{
    @Override
    public void before(Method method, Object[] args, Object target) throws Throwable {
        System.out.println("MyServiceBeforeAdvice");
    }
}

public class MyServiceAfterService implements AfterReturningAdvice{
    @Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
        System.out.println("MyServiceAfterService");
    }
}


public class MyMethodInterceptor implements MethodInterceptor{
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        System.out.println("before");
        Object result = invocation.proceed();
        System.out.println("after");
        return result;
    }
}

对应的xml写法

        <bean id="someService" class="day1207.ServiceImpl"/>

        <bean id="myAdvice" class="day1207.MyServiceBeforeAdvice"/>
        <bean id="myAdvice2" class="day1207.MyServiceAfterService"/>
        <bean id="myAdvice3" class="day1207.MyMethodInterceptor"/>

        <bean id="serviceProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
                <property name="target" ref="someService"/>
                <property name="interceptorNames" value="myAdvice, myAdvice2, myAdvice3"/>
        </bean>

 CGlib代理

---

 Spring中默认有接口的对象直接用的jdk动态代理实现的AOP, 无接口的对象用CGlib实现的.

如果想要强制都用CGlib实现, 则可以通过以下配置

        <property name="optimize" value="true"/>

 或者

        <property name="proxyTargetClass" value="true"/>

Advisor

---

 

PointcutAdvisor: 可以指定具体切入点位置.

NameMatchMethodPointcutAdvisor 名称匹配

        <bean id="myAdvisor" class="org.springframework.aop.support.NameMatchMethodPointcutAdvisor">
                <property name="advice" ref="myAdvice2"/>
                <!-- 匹配对象是简单方法名 -->
                <property name="mappedNames" value="doFirst, doSecond"/>
        </bean>

 RegexpMethodPointcutAdvisor 正则匹配

        <bean id="myAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
                <property name="advice" ref="myAdvice2"/>
                <!--匹配全限定性方法路径-->
                <property name="pattern" value=".*S.*"/>
        </bean>

自动代理生成器

---

用于解决多个Bean需要对应多个代理的问题.

Advisor代理生成器

        <bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator"/>

缺点: 范围太广, 无法指定差异化Bean处理, 不能选择切面类型, 只能Advisor. 内部实现是用的BeanPostProcessor.

Bean名称自动代理生成器

        <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
                <property name="beanNames" value="someService"/>
                <property name="interceptorNames" value="myAdvisor"/>
        </bean>