学习笔记——Spring中的AOP(AspectJ)；Spring中AOP概述；Spring中AOP相关术语；AspectJ中切入点表达式；AspectJ中JoinPoint对象；AspectJ中通知

<!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>5.3.10</version>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">
<!--    开启组件扫描-->
    <context:component-scan base-package="com.hh"></context:component-scan>
<!--    开启AspectJ注解支持-->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>

@Component
@Aspect
public class MyLogging {
    /**
     * 方法之前
     */
    public static void beforeMethod(String methodName,Object[] arg){
        System.out.println("==>Calc中"+methodName+"方法()，参数："+ Arrays.toString(arg));
    }
    /**
     * 方法之后
     */
    public static void afterMethod(String methodName,Object rs){
        System.out.println("==>Calc中"+methodName+"方法()，结果："+rs);
    }
}

 //重用切入点表达式
    @Pointcut("execution(* com.hh.aop.CalcImpl.*(..))")
    public void myPointCut(){}

@Before(value = "myPointCut()")

@After("myPointCut()")

String methodName = joinPoint.getSignature().getName();

Object[] args = joinPoint.getArgs();

@Before(value = "myPointCut()")
    public void beforeMethod(JoinPoint joinPoint){
        //获取方法名称
        String methodName = joinPoint.getSignature().getName();
        //获取参数
        Object[] args = joinPoint.getArgs();
        System.out.println("【前置通知】==>Calc中"+methodName+"方法()，参数："+ Arrays.toString(args));
    }

 @After("myPointCut()")
    public void afterMethod(JoinPoint joinPoint){
        //获取方法名称
        String methodName = joinPoint.getSignature().getName();
        //获取参数
        Object[] args = joinPoint.getArgs();
        System.out.println("【后置通知】==>Calc中"+methodName+"方法()，之后执行："+ Arrays.toString(args));
    }

@AfterReturning(value = "myPointCut()",returning = "rs")
    public void afterReturnning(JoinPoint joinPoint,Object rs){
        //获取方法名称
        String methodName = joinPoint.getSignature().getName();
        //获取参数
        Object[] args = joinPoint.getArgs();
        System.out.println("【返回通知】==>Calc中"+methodName+"方法()，返回结果执行！结果："+ rs);
    }

@AfterThrowing(value = "myPointCut()",throwing = "ex")
    public void afterThrowing(JoinPoint joinPoint,Exception ex){
        //获取方法名称
        String methodName = joinPoint.getSignature().getName();
        //获取参数
        Object[] args = joinPoint.getArgs();
        System.out.println("【异常通知】==>Calc中"+methodName+"方法()，出现异常时执行！异常："+ ex);
    }

 @Around(value = "myPointCut()")
    public Object aroundMethod(ProceedingJoinPoint pjp){
        //获取方法名称
        String methodName = pjp.getSignature().getName();
        //获取参数
        Object[] args = pjp.getArgs();
        //定义返回值
        Object rs = null;
        try {
            //前置通知 ）
            System.out.println("【前置通知】==>Calc中"+methodName+"方法()，参数："+ Arrays.toString(args));
            //触发目标对象的目标方法(加减乘除)
            rs = pjp.proceed();
            //返回通知（有异常不执行
            System.out.println("【返回通知】==>Calc中"+methodName+"方法()，返回结果执行！结果："+ rs);
        } catch (Throwable throwable) {
            throwable.printStackTrace();
            //异常通知
            System.out.println("【异常通知】==>Calc中"+methodName+"方法()，出现异常时执行！异常："+ throwable);
        }finally {
            //后置通知(有异常执行)
            System.out.println("【后置通知】==>Calc中"+methodName+"方法()，之后执行："+ Arrays.toString(args));
        }
        return rs;
    }