spring-AOP

普通的oop工程，方法都是纵向的依次执行的，而aop是当方法执行的时候，执行前后添加额外的一些功能，这种纵向的执行流程称之为面向切面编程（aop）。
这里介绍几个概念：
切点：pointcut，指的是原有的执行方法
前置通知：在切点之前进行的操作befor advice
后置通知：在切点之后进行的操作after advice
切点执行过程中出现异常会触发异常通知throws advice
所有的这些功能叫做切面
织入：把切面织入到原有的功能上叫做织入
代码实现，当一个方法被调用的时候，执行前后分别由林外的操作
前置通知，后置通知类：

package com.shuai.advice;

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

public class AfterAdvice implements AfterReturningAdvice {
    public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
        System.out.println("我先得洗澡，擦润肤乳");
    }
}
package com.shuai.advice;

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class BeforAdvice implements MethodBeforeAdvice {
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println("我要先玩一局王者");
    }
}

原有的功能类：

package com.shuai.domain;

public class people {
    public  void study(){
        System.out.println("我要学习了");
    }
    public  void sleep(){
        System.out.println("我要睡觉了");
    }
}

xml配置：execution(* com.shuai.domain.people.study())星后要有空格

<?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">
<!--配置切点-->
    <aop:config>
        <aop:pointcut id="peopleCut" expression="execution(* com.shuai.domain.people.study())" ></aop:pointcut>
        <aop:advisor advice-ref="beforAdvice" pointcut-ref="peopleCut"></aop:advisor>
        <aop:advisor advice-ref="afterAdvice" pointcut-ref="peopleCut"></aop:advisor>
    </aop:config>
    <!--指定前置通知-->
    <bean id="beforAdvice" class="com.shuai.advice.BeforAdvice"></bean>
    <!--指定后置通知-->
    <bean id="afterAdvice" class="com.shuai.advice.AfterAdvice"></bean>
    <bean id="people" class="com.shuai.domain.people"></bean>
</beans>

测试：

import com.shuai.domain.people;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class test {
    public static void main(String[] args) {
        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("application.xml");
        people p= applicationContext.getBean("people", people.class);
        p.study();
        p.sleep();
    }
}

异常通知：

    <aop:config>
        <aop:aspect ref="advice">
            <aop:pointcut id="peopleCut" expression="execution(* com.shuai.domain.people.study())"></aop:pointcut>
            <aop:after-throwing method="mytestException" pointcut-ref="peopleCut"></aop:after-throwing>
        </aop:aspect>
    </aop:config>
    <bean id="people" class="com.shuai.domain.people"></bean>
    <bean id="advice" class="com.shuai.advice.ExceptionAdvice"></bean>

注解配置aop

package com.shuai.domain;

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

@Component
public class people {
    @Pointcut("execution(* com.shuai.domain.people.study())")
    public  void study(){

        System.out.println("我要学习了");
    }
    public  void sleep(){
        System.out.println("我要睡觉了");
    }

}
package com.shuai.advice;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class BeforAdvice {
    @Before("com.shuai.domain.people.study()")
    public void before()  {
        System.out.println("我要先玩一局王者");
    }
}

xml配置：

    <context:component-scan base-package="com.shuai.domain,com.shuai.advice"></context:component-scan>
    <aop:aspectj-autoproxy proxy-target-class="true"></aop:aspectj-autoproxy>

   ApplicationContext applicationContext=new ClassPathXmlApplicationContext("application.xml");
        people p= applicationContext.getBean("people", people.class);
        p.study();