手动实现 Spring 底层机制实现任务阶段一编写自己 Spring 容器-准备篇【2】

news2025/2/8 2:17:41

😀前言
手动实现 Spring 底层机制的第2篇实现了任务阶段一编写自己 Spring 容器-准备篇【2】

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文章目录

😀手动实现 Spring 底层机制实现任务阶段一编写自己 Spring 容器-准备篇【2】
- 创建SmartAnimalable接口
- 创建SmartDog类
- 创建SmartAnimalAspect切面类
- 修改类beans.xml
- 创建AppMain类
- 输出结果
😄简单分析
- AOP 和 BeanPostProces关系
- 看一下 AnnotationAwareAspectJAutoProxyCreator 的类图
- 分析
- 😄总结

😀手动实现 Spring 底层机制实现任务阶段一编写自己 Spring 容器-准备篇【2】

创建SmartAnimalable接口

public interface SmartAnimalable {
    float getSum(float i, float j);
    float getSub(float i, float j);
}

创建SmartDog类

@Component
public class SmartDog implements SmartAnimalable {

    public float getSum(float i, float j) {
        float res = i + j;
        System.out.println("SmartDog-getSum-res=" + res);
        return res;
    }

    public float getSub(float i, float j) {
        float res = i - j;
        System.out.println("SmartDog-getSub-res=" + res);
        return res;
    }
}

创建SmartAnimalAspect切面类

@Component
@Aspect
public class SmartAnimalAspect {

    //给SmartDog配置前置，返回，异常，最终通知

    //前置通知
    @Before(value = "execution(public float com.wyxde.spring.aop.SmartDog.getSum(float, float))")
    public void showBeginLog(JoinPoint joinPoint) {
        //通过连接点对象joinPoint 可以获取方法签名
        Signature signature = joinPoint.getSignature();
        System.out.println("SmartAnimalAspect-切面类showBeginLog()[使用的myPointCut()]-方法执行前-日志-方法名-" + signature.getName() + "-参数 "
                + Arrays.asList(joinPoint.getArgs()));
    }

   //返回通知
    @AfterReturning(value = "execution(public float com.wyxde.spring.aop.SmartDog.getSum(float, float))", returning = "res")
    public void showSuccessEndLog(JoinPoint joinPoint, Object res) {
        Signature signature = joinPoint.getSignature();
        System.out.println("SmartAnimalAspect-切面类showSuccessEndLog()-方法执行正常结束-日志-方法名-" + signature.getName() + " 返回的结果是=" + res);
    }


   //异常通知
    @AfterThrowing(value = "execution(public float com.wyxde.spring.aop.SmartDog.getSum(float, float))", throwing = "throwable")
    public void showExceptionLog(JoinPoint joinPoint, Throwable throwable) {
        Signature signature = joinPoint.getSignature();
        System.out.println("SmartAnimalAspect-切面类showExceptionLog()-方法执行异常-日志-方法名-" + signature.getName() + " 异常信息=" + throwable);
    }

    //最终通知
    @After(value = "execution(public float com.wyxde.spring.aop.SmartDog.getSum(float, float))")
    public void showFinallyEndLog(JoinPoint joinPoint) {
        Signature signature = joinPoint.getSignature();
        System.out.println("SmartAnimalAspect-切面类showFinallyEndLog()-方法最终执行完毕-日志-方法名-" + signature.getName());
    }

}

修改类beans.xml

配置自动扫描的包, 同时引入对应的名称空间

如果我们是普通的java项目, beans.xml 放在src下
如果我们是java maven 项目, beans.xml 放在 src/main/resources

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



    <context:component-scan base-package="com.wyxde.spring.component"/>
    <context:component-scan base-package="com.wyxde.spring.aop"/>

    <!--启用基于注解方式的AOP功能-->
    <aop:aspectj-autoproxy/>

    <!--配置后置处理器-->
    <bean class="com.wyxde.spring.process.MyBeanPostProcessor" id="myBeanPostProcessor"/>
</beans>

创建AppMain类

public class AppMain {
    public static void main(String[] args) {
        //测试看看是否可以得到spring容器中的bean , 同时看看依赖注入是否OK

        ApplicationContext ioc =
                new ClassPathXmlApplicationContext("beans.xml");
        UserAction userAction = (UserAction) ioc.getBean("userAction");
        UserAction userAction2 = (UserAction) ioc.getBean("userAction");

        System.out.println("userAction=" + userAction);
        System.out.println("userAction2=" + userAction2);

        UserDao userDao = (UserDao) ioc.getBean("userDao");
        System.out.println("userDao=" + userDao);

        UserService userService = (UserService) ioc.getBean("userService");
        System.out.println("userService=" + userService);

        //测试一下当前的依赖注入
        userService.m1();

        //测试一下AOP
        SmartAnimalable smartDog = ioc.getBean(SmartAnimalable.class);
        smartDog.getSum(10, 2);

    }
}