1、通知

目标对象：

package com.sgcc.lms.aop;
@Component("calc")
public class CalcImpl implements Calc {
    @Override
    public int add(int i, int y) {
        int result = i + y;
        return result;
    }
    @Override
    public int sub(int i, int y) {
        int result = i - y;
        return result;
    }
    @Override
    public int mul(int i, int y) {
        int result = i * y;
        return result;
    }
    @Override
    public int div(int i, int y) {
        int result = i / y;
        return result;
    }
}

切面：

package com.sgcc.lms.aop;
import java.util.Arrays;
import org.aspectj.lang.JoinPoint;
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;
/**
 * 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 {
    /**
     * 定义一个方法, 用于声明切入点表达式. 一般地, 该方法中再不需要添入其他的代码. 
     * 使用 @Pointcut 来声明切入点表达式. 
     * 后面的其他通知直接使用方法名来引用当前的切入点表达式. 
     */
    @Pointcut("execution(public int com.sgcc.lms.aop.Calc.*(..))")
    public void declareJointPointExpression(){}
    /**
     * 在 com.atguigu.spring.aop.ArithmeticCalculator 接口的每一个实现类的每一个方法开始之前执行一段代码
     */
    @Before("declareJointPointExpression()")
    public void beforeMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        Object [] args = joinPoint.getArgs();
        System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));
    }
    /**
     * 在方法执行之后执行的代码. 无论该方法是否出现异常
     */
    @After("declareJointPointExpression()")
    public void afterMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends");
    }
    /**
     * 在方法法正常结束受执行的代码
     * 返回通知是可以访问到方法的返回值的!
     */
    @AfterReturning(value="declareJointPointExpression()",
            returning="result")
    public void afterReturning(JoinPoint joinPoint, Object result){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends with " + 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在执行通知代码
     */
    @AfterThrowing(value="declareJointPointExpression()",
            throwing="e")
    public void afterThrowing(JoinPoint joinPoint, Exception e){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " occurs excetion:" + e);
    }
    /**
     * 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, 返回值即为目标方法的返回值
     */
    /*
    @Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
    public Object aroundMethod(ProceedingJoinPoint pjd){
        Object result = null;
        String methodName = pjd.getSignature().getName();
        try {
            //前置通知
            System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
            //执行目标方法
            result = pjd.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;
    }
    */
}

applicationContext.xml

<?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/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
        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-4.0.xsd">
    <!-- <bean id="calc" class="com.sgcc.lms.aop.CalcImpl"></bean> -->
    <!-- 配置自动扫描的包 -->
    <context:component-scan
        base-package="com.sgcc.lms.aop"></context:component-scan>
    <!-- 配置自动为匹配 aspectJ 注解的 Java 类生成代理对象 -->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>

使用

package com.sgcc.lms.aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
         Calc calc = (Calc) ctx.getBean("calc");
        System.out.println(calc.getClass().getName());
        int result = calc.add(1, 2);
        System.out.println("result:" + result);
        result = calc.div(1000, 10);
        System.out.println("result:" + result);
    }
}

依赖

<dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>${springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${springframework.version}</version>
        </dependency>
    </dependencies>

2、spring boot使用注解记录方法耗时

package com.kd.ndmp.dc.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
 * @Author 李孟帅
 * @Date 2021/8/13
 * @Description TODO 方法耗时注解
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface TakeTime {
    String value() default "";
}

环绕通知

package com.kd.ndmp.dc.aspect;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
import java.time.Duration;
import java.time.LocalDateTime;
/**
 * @Author 李孟帅
 * @Date 2021/8/13
 * @Description TODO
 */
@Aspect
@Slf4j
@Component
public class TakeTimeAspect {
    private static final String LINE = "==========================================》{}";
    @Pointcut("@annotation(com.kd.ndmp.dc.annotation.TakeTime)")
    public void pointCut() {
    }
    @Around("pointCut()")
    public Object around(ProceedingJoinPoint joinPoint) {
        Object result = null;
        try {
            LocalDateTime now = LocalDateTime.now();
            result = joinPoint.proceed();
            Duration between = Duration.between(now, LocalDateTime.now());
            log.info("耗时：{}",between.toMillis());
        } catch (Throwable throwable) {
            throwable.printStackTrace();
        }
        return result;
    }
}

使用

注意

使用注解的，该类需要通过spirng ioc容器的bean 管理

只能学一点点

AOP

1、通知

目标对象：

切面：

applicationContext.xml

使用

依赖

2、spring boot使用注解记录方法耗时

使用

注意