Spring AOP 四大通知

时间:2021-08-01 19:13:14

Spring AOP 四大通知

Spring 3.X 以前

1.前置通知,实现  MethodBeforeAdvice 接口,重写

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

    

    import java.lang.reflect.Method;

    import org.springframework.aop.MethodBeforeAdvice;

    public class TestMethodBeforeAdvice implements MethodBeforeAdvice {

        /** arg0  方法

        * arg1 参数

        * arg2 操作对象

        * */

        @Override

        public void before(Method arg0, Object[] arg1, Object arg2) throws Throwable {

          System.out.println("前置通知:----》方法:"+arg0.getName()+"传入参数"+arg1+"操作象"+arg2);

        }

     }

2.后置通知,实现 AfterReturningAdvice  接口,重写

      public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable 方法

      import java.lang.reflect.Method;

      import org.springframework.aop.AfterReturningAdvice;

      public class TestAfterReturningAdvice implements AfterReturningAdvice{

            /**

            * arg0:return 的返回值

            * arg1:执行的方法对象

            * arg2:方法执行中传递过来的参数

            * arg3:执行方法的对象

            */

            @Override

            public void afterReturning(Object arg0, Method arg1, Object[] arg2, Object arg3) throws Throwable {

              System.out.println("后置通知:----》方法:"+arg1.getName()+"返回值:"+arg0+"执行方对象:"+arg3);

            }  

      }

3.环绕通知, 实现 MethodInterceptor  接口,重写

      public  Object  invoke(MethodInvocation  invocation) throws Throwable 方法

      import java.lang.reflect.Method;

      import org.aopalliance.intercept.MethodInterceptor;

      import org.aopalliance.intercept.MethodInvocation;

      public class TestMethodinterceptor implements MethodInterceptor {

          @Override

          public Object invoke(MethodInvocation invocation) throws Throwable {

              Method method = invocation.getMethod() ; //方法

              Object[] objs = invocation.getArguments() ; //参数

              Object obj = invocation.getThis() ; //操作对象

              System.out.println("环绕通知:-----》 开始: 方法:"+method.getName()+"传入的参数:"+objs+" 操作对象:"+obj);

              Object result = invocation.proceed() ;   //放行

              System.out.println("环绕通知:-----》 结束:  返回值:"+result);

              return result ;

          }

      }

4.异常通知,实现 ThrowsAdvice 接口,重写

public void afterThrowing(Method  m, Object  args, Object  target,Throwable  e) 方法

    import java.lang.reflect.Method;

    import org.springframework.aop.ThrowsAdvice;

    public class TestThrowsAdvice implements ThrowsAdvice {

        public void afterThrowing(Method m, Object args, Object target, Throwable e) {

          System.out.println("异常通知:方法"+m.getName()+"发生异常,"+e.getMessage());

           System.exit(0);

        }

     }

注意:查看ThrowsAdvice源码会发现这个接口里面没有定义方法,但是这个方法必须这么写,

Spring 3.X 以后版本

 

    import org.aspectj.lang.JoinPoint;

    import org.aspectj.lang.ProceedingJoinPoint;

    public class TestAdvice {

       public void before(JoinPoint joinPoint){ //前置通知

          System.out.println("操作者"+joinPoint.getTarget()+"参数             "+joinPoint.getArgs()[0]);

          System.out.println("*********************前置通知*********************");

       }

       //后置通知:当方法执行完会触发,出错则不执行

       public void afterReturning(JoinPoint joinPoint,Object obj){

            System.out.println("后置通知");

            System.out.println("返回结果:"+obj);

        }

        //最终通知

        public void after(JoinPoint joinPoint){

            System.out.println("最终通知");

            System.out.println("调用的方法"+joinPoint.getSignature());

        }

        //异常通知

        public void throwAdvice(Exception exception){

            System.out.println("--------异常通知--------");

            System.out.println("异常消息"+exception.getMessage());

        }

        //环绕通知

        public Object around(ProceedingJoinPoint proceedingJoinPoint){

            System.out.println("环绕通知开始");

            try {

              Object  obj = proceedingJoinPoint.proceed() ;

              System.out.println("环绕通知结束");

              return obj ;

            } catch (Throwable e) {

              e.printStackTrace();

            }

            return null ;

      }

  }

配置信息

<!--Spring3.X以前-->

<!--后置通知-->

  <bean id="afterAdvice" class="com.spring.advice.TestAfterReturningAdvice"/>

<!--前置通知-->

  <bean id="beforeAdvice" class="com.spring.advice.TestMethodBeforeAdvice"/>

<!--环绕通知-->

  <bean id="interceptorAdvice" class="com.spring.advice.TestMethodinterceptor"/>

<!--异常通知-->

  <bean id="throwsAdvice" class="com.spring.advice.TestThrowsAdvice"/>

<!--Spring3.X以后整合-->

  <bean id="advice" class="com.spring.advice.TestAdvice"/>

<!-- AOP设置 -->

<aop:config>

    <aop:pointcut expression="execution(* com.spring.service.*.*(..))" id="mycut"/>

    <aop:advisor advice-ref="afterAdvice" pointcut-ref="mycut"/>

    <aop:advisor advice-ref="beforeAdvice" pointcut-ref="mycut"/>

    <aop:advisor advice-ref="interceptorAdvice" pointcut-ref="mycut"/>

    <aop:advisor advice-ref="throwsAdvice" pointcut-ref="mycut"/>

    <!-- 新版本 -->

    <aop:aspect ref="advice">

        <aop:before method="before" pointcut-ref="mycut"/>

        <aop:after-returning method="afterReturning" returning="obj" pointcut-ref="mycut"/>

        <aop:after method="after" pointcut-ref="mycut"/>

        <aop:after-throwing method="throwAdvice" throwing="exception" pointcut-ref="mycut"/>

        <aop:around method="around" pointcut-ref="mycut"/>

     </aop:aspect>

</aop:config>

两种方法:

  Spring3.X版本以前写法思路更清晰,新版本,虽然把4个通知整合在了一起,但是,如果业务复杂的话,通知较多建议分开写,

两种方法区别不是很大,具体还得开需求

expression的value值

任意公共方法的执行:

  execution(public * *(..))

任何一个以“set”开始的方法的执行:

  execution(* set*(..))

AccountService 接口的任意方法的执行:

  execution(* com.xyz.service.AccountService.*(..))

定义在service包里的任意方法的执行:

  execution(* com.xyz.service.*.*(..))

定义在service包或者子包里的任意方法的执行:

  execution(* com.xyz.service..*.*(..))

若要转载,请标明此处