AOP(Aspect Oriented Programming,面向切面编程)通过提供另一种思考程序结构的方式来补充OOP(Object Oriented Programming,面向对象编程）。OOP模块化的关键单元是类，而在AOP中，模块化的单元是切面（Aspect）。切面可以实现跨多个类型和对象之间的事务管理、日志等方面的模块化。
OOP用继承和组合的方式，编制成一套类和对象的体系；而AOP凡某包某类某命名方法，一并同样处理（正则表达式）。
AOP核心概念
1：Aspect（切面）
2：Join Point(连接点）
3：Advice（通知/增强）
4：Pointcut：（切入点）
5：Introduction（引入）
6：Target Object（目标对象）
7：AOP Proxy（AOP代理）
8：Weaving(织入）
其中Advice的类型：
1.Before Adivce(前置通知）
2.After Returning Advice(返回后通知）
3.After Throwing Advice(抛出异常后通知）
4.After(finally)Advice(最后通知)
5.Around Advice(环绕通知）
前置增强：
pom.xml中添加依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.spring</groupId>
<artifactId>AoP</artifactId>
<version>1.0-SNAPSHOT</version>
<name>AoP</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<spring.version>5.1.5.RELEASE</spring.version>
<aspectj.version>1.9.2</aspectj.version>
<junit.version>4.12</junit.version>
<log4j.version>1.2.17</log4j.version>
<slf4j.version>1.7.12</slf4j.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<!--spring-aop依赖-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<!--aspectj依赖-->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${aspectj.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>${aspectj.version}</version>
</dependency>
<!--spring-test依赖-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
<!--Lombok依赖-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.18</version>
</dependency>
<!-- log4j日志依赖 -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
</dependencies>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
hello实例代码：
Hello接口：
package com.spring.Aop;
/**
* Created by User on 2019/3/7.
*/
public interface Hello {
String getHello();
}
实现类：
package com.spring.Aop;
/**
* Created by User on 2019/3/7.
*/
public class HelloImpl implements Hello{
@Override
public String getHello() {
return "Hello,Spring Aop";
}
}
MyBeforeAdvice:
package com.spring.Aop;
/**
* Created by User on 2019/3/7.
* 用户自定义的前置增强类
*/
public class MyBeforeAdvice {
// 定义前置方法
public void beforeMethod(){
System.out.println("This is a before method.");
}
}
配置文件：
<!--配置一个Hello的bean,等同于Hello hello=new HelloImpl();-->
<bean id="hello" class="com.spring.Aop.HelloImpl"/>
<!--配置一个MyBeforeAdvice前置增强的bean-->
<bean id="myBeforeAdvice" class="com.spring.Aop.MyBeforeAdvice"/>
<!--配置aop-->
<aop:config>
<aop:aspect id="before" ref="myBeforeAdvice">
<aop:pointcut id="myPointCut" expression="execution(* com.spring.Aop.*.*(..))"/>
<aop:before method="beforeMethod" pointcut-ref="myPointCut"/>
</aop:aspect>
</aop:config>
HelloApp:
package com.spring.Aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Created by User on 2019/3/7.
*/
public class HelloAPP {
public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("Spring.xml");
Hello hello=context.getBean(Hello.class);
System.out.println(hello.getHello());
}
}
结果.png
