详解Spring中的AOP及AspectJ五大通知注解

<?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.ycfxhsw.aop"></context:component-scan>
    <!-- 使用AspactJ，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>

public interface Calc {
    // 加法
    int Addition(int i, int j);
    // 减法
    int Subtraction(int i, int j);
    // 乘法
    int Multiplication(int i, int j);
    // 除法
    int Division(int i, int j);
}

import org.springframework.stereotype.Component;
@Component
public class CalcImp implements Calc {
    public int Addition(int i, int j) {
        int result = i + j;
        return result;
    }
    public int Subtraction(int i, int j) {
        int result = i + j;
        return result;
    }
    public int Multiplication(int i, int j) {
        int result = i + j;
        return result;
    }
    public int Division(int i, int j) {
        int result = i + j;
        return result;
    }
}

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import java.util.Arrays;
import java.util.List;
// @Order(1) 指定切面优先级
@Component
@Aspect
public class LoggingAspect {
    /**
     * 申明切入点表达式，一般该方法内不需要添加其他方法
     * 使用 @Pointcut 申明切入点表达式
     * 后面的切入点直接使用方法名
     */
    @Pointcut("execution(public int com.ycfxhsw.aop.Calc.*(..))")
    public void DeclareJoinPointExpression() {
    }
    /**
     * 前置通知
     * @param joinPoint
     */
    @Before("execution(public int com.ycfxhsw.aop.Calc.*(int, int))")
    public void BeforeMethod(JoinPoint joinPoint) {
        String MethodName = joinPoint.getSignature().getName();
        List<Object> list = Arrays.asList(joinPoint.getArgs());
        System.out.println("Method Starts..." + MethodName + " with " + list);
    }
    /**
     * 后置通知（无论有无异常）
     * 不能访问目标方法的执行结果
     * @param joinPoint * com.ycfxhsw.aop.Calc.*(..)
     * 重用 DeclareJoinPointExpression()
     */
    @After("DeclareJoinPointExpression()")
    public void AfterMethod(JoinPoint joinPoint) {
        String MethodName = joinPoint.getSignature().getName();
        System.out.println("Method Ends..." + MethodName);
    }
    /**
     * 返回通知
     * 在方法正常结束后执行
     * 可以访问目标方法的执行结果
     * @param joinPoint,result
     */
    @AfterReturning(value = "execution(public int com.ycfxhsw.aop.Calc.*(..))", returning = "result")
    public void AfterReturningMethod(JoinPoint joinPoint, Object result) {
        String MethodName = joinPoint.getSignature().getName();
        System.out.println("Method AfterReturning..." + MethodName + " --> " + result);
    }
    /**
     * 异常通知
     * @param joinPoint,exception
     */
    @AfterThrowing(value = "execution(public int com.ycfxhsw.aop.Calc.*(..))", throwing = "exception")
    public void AfterThrowingMethod(JoinPoint joinPoint, Exception exception) {
        String MethodName = joinPoint.getSignature().getName();
        System.out.println("Method AfterThrowing..." + MethodName + " --> " + exception);
    }
    /**
     * 环绕通知，需要携带 ProceedingJoinPoint 类型的参数
     * 类似于动态代理全过程
     * 必须有返回值（目标方法返回值）
     * @param proceedingJoinPoint
     @Around("execution(public int com.ycfxhsw.aop.Calc.*(..))")
     public Object AroundMethod(ProceedingJoinPoint proceedingJoinPoint) {
     Object result = null;
     String methodName = proceedingJoinPoint.getSignature().getName();
     try {
     // 前置通知
     System.out.println("The method " + methodName + " begins with " + Arrays.asList(proceedingJoinPoint.getArgs()));
     // 执行目标方法
     result = proceedingJoinPoint.proceed();
     // 返回通知
     System.out.println("The method " + methodName + " ends with " + result);
     } catch (Throwable e) {
     // 异常通知
     System.out.println("The method " + methodName + " occurs exception:" + e);
     throw new RuntimeException(e);
     }
     // 后置通知
     System.out.println("The method " + methodName + " ends");
     return result;
     }
     */
}

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * 测试
 */
public class Main {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("Calc.xml");
        Calc calc = applicationContext.getBean(Calc.class);
        System.out.println(calc.getClass().getName());
        int resultAdd = calc.Addition(5, 6);
        System.out.println("result-->" + resultAdd + "\n");
        int resultSub = calc.Subtraction(9, 3);
        System.out.println("result-->" + resultSub + "\n");
        int resultMul = calc.Multiplication(8, 6);
        System.out.println("result-->" + resultMul + "\n");
        int resultDiv = calc.Division(99, 3);
        System.out.println("result-->" + resultDiv + "\n");
    }
}