Spring中常用三种通知

(1)前置通知

接口：org.springframework.aop.MethodBeforeAdvice

使用前置通知可以在联结点执行前进行自定义的操作。不过，Spring里只有一种联结点，即方法调用，所以前置通知事实上就是让你能在方法调用前进行一些操作。前置通知可以访问调用的目标方法，也可以对该方法的参数进行操作，不过它不能影响方法调用本身。

 

示例：

 

IHello接口

public interface IHello {

    public void hello(String name);

}

 

IHello接口实现

public class HelloSpeaker implements IHello {

    public void hello(String name) {

        System.out.println("Hello, " + name);

    }

}

 

IHello实现代理

public class LogBeforeAdvice implements MethodBeforeAdvice {

    private Logger logger = Logger.getLogger(this.getClass().getName());

   

    public void before(Method method, Object[] args, Object target) throws Throwable {

        logger.log(Level.INFO, "method starts..." + method);

   }

}

 

Spring配置文件

    <bean id="logBeforeAdvice"

          class="onlyfun.caterpillar.LogBeforeAdvice"/>

 

    <bean id="helloSpeaker"

          class="onlyfun.caterpillar.HelloSpeaker"/>

   

    <bean id="helloProxy"

          class="org.springframework.aop.framework.ProxyFactoryBean">

        <property name="proxyInterfaces">

            <value>onlyfun.caterpillar.IHello</value>

        </property>

        <property name="target">

            <ref bean="helloSpeaker"/>

        </property>

        <property name="interceptorNames">

            <list>

                <value>logBeforeAdvice</value>

            </list>

        </property>

    </bean>

 

 

测试类

public class SpringAOPDemo {

    public static void main(String[] args) {

        ApplicationContext context =

                new FileSystemXmlApplicationContext(

                        "beans-config.xml");

        IHello helloProxy =

            (IHello) context.getBean("helloProxy");

        helloProxy.hello("Justin");

    }

}

 

(2)后置通知(或返回后通知)

接口：org.springframework.aop.AfterReturningAdvice

后置通知在联结点处的方法调用已经完成，并且已经返回一个值时运行，后置通知可以访问调用的目标方法，以及该方法的参数和返回值。因为等到通知执行时该方法已经调用，后置通知完全不能影响方法调用本身。

 

示例：

 

IHello接口

public interface IHello {

    public void hello(String name);

}

 

IHello接口实现

public class HelloSpeaker implements IHello {

    public void hello(String name) {

        System.out.println("Hello, " + name);

    }

}

 

IHello实现代理

public class LogAfterAdvice implements AfterReturningAdvice {

    private Logger logger = Logger.getLogger(this.getClass().getName());

   

    public void afterReturning(Object object, Method method,

                               Object[] args,

                               Object target) throws Throwable {

        logger.log(Level.INFO, "method ends..." + method);

   }

}

 

Spring配置文件

    <bean id="logAfterAdvice"

          class="onlyfun.caterpillar.LogAfterAdvice"/>

 

    <bean id="helloSpeaker"

          class="onlyfun.caterpillar.HelloSpeaker"/>

   

    <bean id="helloProxy"

          class="org.springframework.aop.framework.ProxyFactoryBean">

        <property name="proxyInterfaces">

            <value>onlyfun.caterpillar.IHello</value>

        </property>

        <property name="target">

            <ref bean="helloSpeaker"/>

        </property>

        <property name="interceptorNames">

            <list>

                <value>logAfterAdvice</value>

            </list>

        </property>

    </bean>

 

测试类

public class SpringAOPDemo {

    public static void main(String[] args) {

        ApplicationContext context = new FileSystemXmlApplicationContext(

                        "beans-config.xml");

        IHello helloProxy = (IHello) context.getBean("helloProxy");

        helloProxy.hello("Justin");

    }

}

 

 

 

(3)包围通知

接口：org.aopalliance.intercept.MethodInterceptor

Spring中的包围通知模AOP联盟的“方法拦截器”标准。包围通知可以在目标方法之前和之后动行，我们也可以定义在什么时候调用目标方法。如果需要，我们也可以另写自己的逻辑而完全不调用目标方法。

 

示例：

 

IHello接口

public interface IHello {

    public void hello(String name);

}

 

 

 

IHello接口实现

public class HelloSpeaker implements IHello {

    public void hello(String name) {

        System.out.println("Hello, " + name);

    }

}

 

IHello实现代理

public class LogInterceptor implements MethodInterceptor {

    private Logger logger = Logger.getLogger(this.getClass().getName());

   

   public Object invoke(MethodInvocation methodInvocation) throws Throwable {

        logger.log(Level.INFO, "method starts..." + methodInvocation.getMethod());

        

        Object result = null;

        try {

          result = methodInvocation.proceed();

        }

        finally {

            logger.log(Level.INFO, "method ends..." +

               methodInvocation.getMethod() + "\n");

        }

        return result;

   }

 

Spring配置文件

    <bean id="logInterceptor"

          class="onlyfun.caterpillar.LogInterceptor"/>

   

    <bean id="helloSpeaker"

          class="onlyfun.caterpillar.HelloSpeaker"/>

   

    <bean id="helloProxy"

          class="org.springframework.aop.framework.ProxyFactoryBean">

        <property name="proxyInterfaces">

            <value>onlyfun.caterpillar.IHello</value>

        </property>

        <property name="target">

            <ref bean="helloSpeaker"/>

        </property>

        <property name="interceptorNames">

            <list>

                <value>logInterceptor</value>

            </list>

        </property>

    </bean>

 

测试类

public class SpringAOPDemo {

    public static void main(String[] args) {

        ApplicationContext context = new FileSystemXmlApplicationContext(

                        "beans-config.xml");

        IHello helloProxy = (IHello) context.getBean("helloProxy");

        helloProxy.hello("Justin");

    }