Spring的IOC和AOP原理及其使用

IOC(要做到编译期不依赖，运行期才依赖)

传统模式
Spring的处理方式
采用了工厂模式，降低了类之间的耦合度

基于动态代理增强代码功能，降低了业务模块之间的耦合度，有两种代理方式：

1. JDK动态代理 (基于接口的动态代理)
2. cglib动态代理(基于子类的动态代理)
   

AOP

引入依赖：

<dependency>
    <groupId>org.aspectjgroupId>
    <artifactId>aspectjweaverartifactId>
    <version>1.9.6version>
dependency>

5种通知类型理解

xml方式：

<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.frank"/>
    
    <aop:config>
        
        <aop:aspect ref="logger">
            
            <aop:pointcut id="loggerPointcut" expression="execution(* com.frank.service..*(..))"/>
            
            <aop:before method="before" pointcut-ref="loggerPointcut"/>
            
            <aop:after-returning method="afterReturning" pointcut-ref="loggerPointcut"/>
            
            <aop:after method="after" pointcut-ref="loggerPointcut"/>
        aop:aspect>
    aop:config>
beans>

xml+注解方式：

<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.frank"/>
    
    <aop:aspectj-autoproxy/>
beans>

package com.frank.advice;

import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class Logger {
    @Pointcut("execution(* com.frank.service..*(..))")
    public void point() {
    }

    @Before("point()")
    public void before() {
        System.out.println("前置通知");
    }

    @AfterReturning("point()")
    public void afterReturning() {
        System.out.println("后置通知");
    }

    @After("point()")
    public void after() {
        System.out.println("最终通知");
    }

}

纯注解配置：

<aop:aspectj-autoproxy/>

将上面xml配置改成在主配置类上加@EnableAspectJAutoProxy开启注解支持