package com.cn.spring.aop.impl;

//加减乘除的接口类

public interface ArithmeticCalculator {

    int add(int i, int j);

    int sub(int i, int j);

    int mul(int i, int j);

    int div(int i, int j);

}

package com.cn.spring.aop.impl;

import org.springframework.stereotype.Component;

//实现类

@Component

public class ArithmeticCalculatorImpl implements ArithmeticCalculator {

    @Override

    public int add(int i, int j) {

        int result = i + j;

        return result;

    }

    @Override

    public int sub(int i, int j) {

        int result = i - j;

        return result;

    }

    @Override

    public int mul(int i, int j) {

        int result = i * j;

        return result;

    }

    @Override

    public int div(int i, int j) {

        int result = i / j;

        return result;

    }

}

package com.cn.spring.aop.impl;

import org.aspectj.lang.JoinPoint;

import org.aspectj.lang.ProceedingJoinPoint;

import org.aspectj.lang.annotation.*;

import org.springframework.core.annotation.Order;

import org.springframework.stereotype.Component;

import java.util.Arrays;

import java.util.List;

//把这个类声明为一个切面：首先需要把该类放入到IOC容器中，在声明为一个切面

//可以使用@order注解指定切面的优先级，值越小，优先级越高

@Order(2)

@Aspect

@Component

public class LoggingAspect {

    //声明该方法是一个前置通知：在目标方法开始之前执行

    @Before("execution(public int ArithmeticCalculator.*(int, int))")

    public void beforeMethod(JoinPoint joinPoint) {

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

        List<Object> args = Arrays.asList(joinPoint.getArgs());

        System.out.println("The method " +  methodName + " begins with " + args);

    }

    //后置通知：在目标方法执行后（无论是否发生异常），执行的通知

    //在后置通知中还不能访问目标方法执行的结果

    @After("execution(public int ArithmeticCalculator.*(int, int))")

    public void afterMethod(JoinPoint joinPoint) {

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

        List<Object> args = Arrays.asList(joinPoint.getArgs());

        System.out.println("The method " +  methodName + " ends with " + args);

    }

    /**

     * 在方法正常结束后执行的代码

     * 返回通知是可以访问到方法的返回值

     * @param joinPoint

     */

    @AfterReturning(value = "execution(public int ArithmeticCalculator.*(int, int))",

    returning = "result")

    public void afterReturning(JoinPoint joinPoint, Object result) {

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

        List<Object> args = Arrays.asList(joinPoint.getArgs());

        System.out.println("The method  ends witd " + result);

    }

    //在目标方法出现异常时会执行的代码

    //可以访问到异常对象；且可以指定在出现特定异常时再执行通知代码

    @AfterThrowing(value = "execution(public int ArithmeticCalculator.*(int, int))",

            throwing = "ex")

    public void afterReturning(JoinPoint joinPoint, Exception ex) {

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

        System.out.println("The method " +  methodName + " occures exception with: " + ex);

    }

    /**

     * 环绕通知需要携带ProceedingJoinPoint类型的参数

     * 环绕通知类似于动态代理的全过程：ProceedingJoinPoint类型的参数可以决定是否执行目标方法

     * 且环绕通知必须有返回值，返回值为目标方法的返回值

     * @param proceedingJoinPoint

     */

    @Around("execution(public int ArithmeticCalculator.*(int, int))")

    public Object aroundMethod(ProceedingJoinPoint proceedingJoinPoint) {

        Object result = null;

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

        //执行目标方法

        try {

            //前置通知

            System.out.println("The method " +  methodName + " begins with " + Arrays.asList(proceedingJoinPoint.getArgs()));

            result = proceedingJoinPoint.proceed();

            //返回通知

            System.out.println("The method ends with " + result);

        } catch (Throwable throwable) {

            //异常通知

            System.out.println("The method " +  methodName + " occures exception with: " + throwable);

            throw new RuntimeException(throwable);

        }

        //后置通知

        System.out.println("The method " +  methodName + " ends");

        return result;

    }

}

package com.cn.spring.aop.impl;

import org.aspectj.lang.JoinPoint;

import org.aspectj.lang.annotation.Aspect;

import org.aspectj.lang.annotation.Before;

import org.springframework.core.annotation.Order;

import org.springframework.stereotype.Component;

import java.util.Arrays;

/**

 * Created by jecyhw on 2015/6/21.

 */

@Order(1)

@Aspect

@Component

public class ValidationAspect {

    @Before("execution(public int ArithmeticCalculator.*(..))")

    public void validateArgs(JoinPoint joinPoint) {

        System.out.println("validate:" + Arrays.asList(joinPoint.getArgs()));

    }

}

package com.cn.spring.aop.impl;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {

    public static void main(String[] args) {

        //1.创建Spring的IOC容器

        ApplicationContext ctx = new ClassPathXmlApplicationContext("17-1.xml");

        //2.从IOC容器中huo获取bean的实例

        ArithmeticCalculator arithmeticCalculator = ctx.getBean(ArithmeticCalculator.class);

        //3.使用bean

        int result = arithmeticCalculator.add(3, 6);

        System.out.println("result:" + result);

        //result = arithmeticCalculator.div(3, 0);

       // System.out.println("result:" + result);

    }

}

<?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 http://www.springframework.org/schema/context/spring-context.xsd

       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

    <context:component-scan base-package="com.cn.spring.aop.impl">

    </context:component-scan>

    <!--使AspjectJ注解起作用：自动为匹配的类生成代理对象-->

    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

</beans>