springAOP-使用注解创建切面

柔情只为你懂 2021-10-19 18:08 385阅读 0赞

1 目标对象

package com.musi.bean;
    import org.springframework.stereotype.Component;
    @Component
    public class Animal {
    
        public void run(){
            System.out.println("animal is running .....");
        }
    
        public void run(String  name){
            System.out.println(name+" is running ........");
        }
    
        public void run(int times){
            System.out.println("animal running times:"+times);
        }
    }

2 切面

package com.musi.aop.annotationaspect;
    
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.AfterReturning;
    import org.aspectj.lang.annotation.AfterThrowing;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class AnimalAspect {
    
        @Before("execution(* com.musi.bean.Animal.run(..))")
        public void beforeRunning(){
            System.out.println("annotation before running .......");
        }
    
        @After("execution(* com.musi.bean.Animal.run(..))")
        public void afterRunning(){
            System.out.println("annotation after running .......");
        }
    
        @AfterReturning("execution(* com.musi.bean.Animal.run(..))")
        public void afterReturning(){
            System.out.println("annotation afterReturning running .......");
        }
    
        @AfterThrowing("execution(* com.musi.bean.Animal.run(..))")
        public void afterThrowing(){
            System.out.println("annotation afterThrowing running .......");
        }
    }

简化写法:

package com.musi.aop.annotationaspect;
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.AfterReturning;
    import org.aspectj.lang.annotation.AfterThrowing;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class AnimalAspectSimple {
    
        @Pointcut("execution(* com.musi.bean.Animal.run())")
        public void run(){}
    
        @Before("run()")
        public void beforeRunning(){
            System.out.println("before running .......");
        }
    
        @After("run()")
        public void afterRunning(){
            System.out.println("after running .......");
        }
    
        @AfterReturning("run()")
        public void afterReturning(){
            System.out.println("afterReturning running .......");
        }
    
        @AfterThrowing("run()")
        public void afterThrowing(){
            System.out.println("afterThrowing running .......");
        }
    }

备注:上述代码中使用了@Pointcut注解,其中performance()方法的名称和实际内容并不重要,在这里它实际上应该是空的,它本身只不过是一个标识,供@Pointcut注解依附.需要注意的是此时除了注解和没有实际操作的performance()方法,Audience类依然是一个pojo,这与普通的Java类并没有什么区别,只不过通过注解表名会被最为切面使用.

3 如果就此止步的话,Audience只会是spring容器中普通的bean,即便使用了AspectJ,但它并不会被视为切面,还需要另作配置.使用Javaconfig的话,可以在配置类的类级别上通过使用EnableAspectJ-AutoProxy注解启用自动代理功能,代码如下:

package com.musi.config;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.EnableAspectJAutoProxy;
    
    @Configuration
    @EnableAspectJAutoProxy
    @ComponentScan("com.musi")
    public class SystemConfig {
    
    }

相应的xml配置如下:

<?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
    		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.musi"/>
        <aop:aspectj-autoproxy />
    
    </beans>

4 测试类

package com.musi.test.bean;
    
    import com.musi.aop.annotationaspect.Encoreable;
    import com.musi.bean.Animal;
    import com.musi.config.SystemConfig;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = SystemConfig.class)
    public class SpringBeanTest {
    
        @Autowired
        private Animal animal;
    
        @Test
        public void test(){
            animal.run();
        }
    }

使用xml配置时的测试类

package com.musi.test.bean;
    
    import com.musi.bean.Animal;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration({"classpath:application.xml"})
    public class SpringXmlTest {
        @Autowired
        private Animal animal;
    
        @Test
        public void test(){
            animal.run();
        }
    }

5 创建环绕通知

package com.musi.aop.annotationaspect;
    
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class AnimalRoundAspect {
        @Pointcut("execution(* com.musi.bean.Animal.run(..))")
        public void run(){}
    
        @Around("run()")
        public void aroundRunning(ProceedingJoinPoint pjp){
            try {
                System.out.println("around before ....");
                pjp.proceed();
                System.out.println("around after ....");
            }catch (Throwable throwable) {
                System.out.println("around trowing ....");
                throwable.printStackTrace();
            }
        }
    }

测试类同上

6 处理通知中的参数

package com.musi.aop.annotationaspect;
    
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.AfterReturning;
    import org.aspectj.lang.annotation.AfterThrowing;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class AnimalArgsAspect {
    
        @Pointcut("execution(* com.musi.bean.Animal.run(int))&&args(times)")
        public void run(int times){}
    
        @Before("run(times)")
        public void beforeRunning(int times){
            System.out.println("before running times:"+times);
        }
    
        @After("run(times)")
        public void afterRunning(int times){
            System.out.println("after running times:"+times);
        }
    
        @AfterReturning("run(times)")
        public void afterReturning(int times){
            System.out.println("afterReturning running times:"+times);
        }
    
        @AfterThrowing("run(times)")
        public void afterThrowing(int times){
            System.out.println("afterThrowing running times:"+times);
        }
    }

测试类

package com.musi.test.bean;
    
    import com.musi.bean.Animal;
    import com.musi.config.SystemConfig;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = SystemConfig.class)
    public class SpringBeanArgsTest {
    
        @Autowired
        private Animal animal;
    
        @Test
        public void test(){
            animal.run(11);
        }
    }

7 通过注解引入新功能

1.  创建引入的代理

package com.musi.aop.annotationaspect;
    
    public interface Encoreable {
        void jump();
    }

1.  代理默认实现类

package com.musi.aop.annotationaspect;
    
    public class EncoreableImpl implements Encoreable {
        public void jump() {
            System.out.println("this is EncoreableImpl.....");
        }
    }

3)通过DeclareParents设置代理

package com.musi.aop.annotationaspect;
    
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.DeclareParents;
    import org.springframework.stereotype.Component;
    
    @Aspect
    @Component
    public class EncoreableIntroducer  {
    
        @DeclareParents(value="com.musi.bean.Animal",defaultImpl=EncoreableImpl.class)
        public static Encoreable encoreable;
    }

说明:@DeclareParents注解有三部分组成:  
value属性指定了哪种类型的bean要引入该接口.在本例中也就是Animal.(如果Animal是接口的话可以在Animal后加上加号,即"com.musi.bean.Animal+",表示是Animal的所有子类型,而不是Animal本身)  
defaultImpl属性指定了为引入功能提供实现的类.在这里我们指定的是DefaultEncoreable提供实现  
@DeclareParents注解所标注的静态属性指明了要引入接口.在这里我们引入的是Encoreable接口.  
此外,我们需要将EncoreableIntroducer声明为一个bean:

4)测试类