AOP

相关概念

• https://blog.csdn.net/q982151756/article/details/80513340

使用

• 依赖

<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.6</version>
</dependency>

使用Spring实现Aop

方式一：使用Spring的API接口

• UserService接口

package com.service;

public interface UserService {
    public void add();

    public void delete();

    public void update();

    public void select();
}

• 实现类

package com.service;

public class UserServiceImpl implements UserService{
    @Override
    public void add() {
        System.out.println("add");
    }

    @Override
    public void delete() {
        System.out.println("delete");
    }

    @Override
    public void update() {
        System.out.println("update");
    }

    @Override
    public void select() {
        System.out.println("select");
    }
}

• 日志类

package com.log;

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class log implements MethodBeforeAdvice {
    @Override
    //method：要执行目标对象的方法
    //objects：参数
    //o：目标参数
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println(o.getClass().getName() + "的" + method.getName() + "被执行了");
    }
}

package com.log;

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

public class AfterLog implements AfterReturningAdvice {
    //o：返回值
    @Override
    public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
        System.out.println("执行了" + method.getName() + "，返回结果为" + o);
    }
}

• 配置文件

<?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: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/aop https://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="com.service.UserServiceImpl"/>
    <bean id="log" class="com.log.log"/>
    <bean id="afterLog" class="com.log.AfterLog"/>

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

        <aop:advisor advice-ref="log" pointcut-ref="pointcut"/>
        <aop:advisor advice-ref="afterLog" pointcut-ref="pointcut"/>
    </aop:config>
</beans>

• 测试类

@Test
public void test1(){
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
    UserService userService = context.getBean("userService", UserService.class);
    userService.add();
}
/*
com.service.UserServiceImpl的add被执行了
add
执行了add，返回结果为null
*/

自定义类实现Aop

• DiyPointCut.java

public class DiyPointCut {
    public void before() {
        System.out.println("方法执行前");
    }

    public void after() {
        System.out.println("方法执行后");
    }
}

• 配置文件

<?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: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/aop https://www.springframework.org/schema/aop/spring-aop.xsd">

    <bean id="userService" class="com.service.UserServiceImpl"/>
    
    <bean id="diy" class="com.diy.DiyPointCut"/>
    
    <aop:config>
        <aop:aspect ref="diy">
            <aop:pointcut id="point" expression="execution(* com.service.UserServiceImpl.*(..))"/>
            <aop:before method="before" pointcut-ref="point"/>
            <aop:after method="after" pointcut-ref="point"/>
        </aop:aspect>
    </aop:config>
    
</beans>

注解实现

• java

package com.diy;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AnnotationPointCut {
    @Before("execution(* com.service.UserServiceImpl.*(..))")
    public void before() {
        System.out.println("方法执行前");
    }

    @After("execution(* com.service.UserServiceImpl.*(..))")
    public void after() {
        System.out.println("方法执行后");
    }

    @Around("execution(* com.service.UserServiceImpl.*(..))")
    public void around(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("环绕前");
        //执行方法
        Object proceed = joinPoint.proceed();
        System.out.println("环绕后");
    }
}

• 配置

<bean id="userService" class="com.service.UserServiceImpl"/>
<bean id="annotationPointCut" class="com.diy.AnnotationPointCut"/>
<aop:aspectj-autoproxy/>

• Test

@Test
public void test1(){
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
    UserService userService = context.getBean("userService", UserService.class);
    userService.add();
}

Aop