类DataSourceAdvice实现MethodBeforeAdvice,没起作用

类DataSourceAdvice.java

 public class DataSourceAdvice implements MethodBeforeAdvice {  
    // service方法执行之前被调用 

    @Override
    public void before(Method method, Object[] args, Object target) throws Throwable {  
        System.out.println("切入点: " + target.getClass().getName() + "类中" + method.getName() + "方法");  
        if(method.getName().startsWith("add")   
            || method.getName().startsWith("create")  
            || method.getName().startsWith("save")  
            || method.getName().startsWith("edit")  
            || method.getName().startsWith("update")  
            || method.getName().startsWith("delete")  
            || method.getName().startsWith("remove")){  
            System.out.println("切换到: master");  
            DataSourceSwitcher.setMaster();  
        }  
        else  {  
            System.out.println("切换到: slave");  
            DataSourceSwitcher.setSlave();  
        }  
    }  
} 

实现MethodBeforeAdvice,重载before方法.在spring.xml

 <bean id="dataSourceAdvice" class="com.sly.spring.DataSourceAdvice" />
    <aop:config>

        <aop:pointcut id="transacationPointcut" expression="execution(* com.sly.service.*.*(..))" />
        <aop:advisor advice-ref="dataSourceAdvice"  pointcut-ref="transacationPointcut" />
 </aop:config>

但是为什么我请求Service时,切面的内容没有打印呢?