多个SpringAOP切面的优先级

蔚落 2021-08-29 13:48 352阅读 0赞

# 多个SpringAOP切面的优先级 #

关于如何创建SpringAOP：https://blog.csdn.net/weixin\_45747080/article/details/106364788

切面有三种方式可以定义优先级：

*  基于`@Order`注解
 *  基于`Ordered`接口配置
 *  基于`XML`配置

## 1、基于注解 ##

@Aspect
    @Order(1)
    public class AspectAdvice1 { 
        //定义切点
        @Pointcut("execution(* cn.wqk.service.UserServiceImpl.*(..))")
        public void pointcut(){ }
    
        //before前置通知
        @Before("pointcut()")
        public void before(){ 
            System.out.println("before前置通知");
        }
    
        //after后置通知
        @After("pointcut()")
        public void after(){ 
            System.out.println("after后置通知");
        }
    
        //around环绕通知
        @Around("pointcut()")
        public Object around(ProceedingJoinPoint point)throws Throwable{ 
            System.out.println("around环绕通知之前——————");
            Object object = point.proceed();
            System.out.println("around环绕通知之后——————");
            return object;
        }
    
        //after-returning返回通知
        @AfterReturning("pointcut()")
        public void afterReturning(){ 
            System.out.println("after-returning返回通知");
        }
    
        //after-throwing异常通知
        @AfterThrowing("pointcut()")
        public void afterThrowing(){ 
            System.out.println("after-throwing异常通知");
        }
    }

@Aspect
    @Order(0)
    public class AspectAdvice { 
        //定义切点
        @Pointcut("execution(* cn.wqk.service.UserServiceImpl.*(..))")
        public void pointcut(){ }
    
        //before前置通知
        @Before("pointcut()")
        public void before(){ 
            System.out.println("before前置通知");
        }
    
        //after后置通知
        @After("pointcut()")
        public void after(){ 
            System.out.println("after后置通知");
        }
    
        //around环绕通知
        @Around("pointcut()")
        public Object around(ProceedingJoinPoint point)throws Throwable{ 
            System.out.println("around环绕通知之前——————");
            Object object = point.proceed();
            System.out.println("around环绕通知之后——————");
            return object;
        }
    
        //after-returning返回通知
        @AfterReturning("pointcut()")
        public void afterReturning(){ 
            System.out.println("after-returning返回通知");
        }
    
        //after-throwing异常通知
        @AfterThrowing("pointcut()")
        public void afterThrowing(){ 
            System.out.println("after-throwing异常通知");
        }
    }

在`@Aspect`注解下添加`@Order()`注解，里面数字越小，优先级越高，同时也需要在spring-aop.xml文件里注册：

<bean name="userService" class="cn.wqk.service.UserServiceImpl"/>
        <bean name="aspectAdvice1" class="cn.wqk.aop.AspectAdvice1"/>
    	<bean name="aspectAdvice" class="cn.wqk.aop.AspectAdvice"/>
        
        <aop:aspectj-autoproxy/>

## 2、基于接口 ##

只需要实现Ordered接口，然后用getOrder()方法返回切面优先级，同样是数字越小，优先级越高

@Aspect
    public class AspectAdvice implements Ordered { 
        //定义切点
        @Pointcut("execution(* cn.wqk.service.UserServiceImpl.*(..))")
        public void pointcut(){ }
    
        //before前置通知
        @Before("pointcut()")
        public void before(){ 
            System.out.println("before前置通知");
        }
    
        //after后置通知
        @After("pointcut()")
        public void after(){ 
            System.out.println("after后置通知");
        }
    
        //around环绕通知
        @Around("pointcut()")
        public Object around(ProceedingJoinPoint point)throws Throwable{ 
            System.out.println("around环绕通知之前——————");
            Object object = point.proceed();
            System.out.println("around环绕通知之后——————");
            return object;
        }
    
        //after-returning返回通知
        @AfterReturning("pointcut()")
        public void afterReturning(){ 
            System.out.println("after-returning返回通知");
        }
    
        //after-throwing异常通知
        @AfterThrowing("pointcut()")
        public void afterThrowing(){ 
            System.out.println("after-throwing异常通知");
        }
    
        @Override
        public int getOrder() { 
            return 0;
        }
    }

@Override
        public int getOrder() { 
            return 0;//定义该切面优先级为0
        }

同样也需要注册到spring-aop.xml里。

## 3、基于XML配置文件 ##

重新定义切面：

public class Aspect { 
        //before前置通知
        public void before(){ 
            System.out.println("before前置通知");
        }
        //after后置通知
        public void after(){ 
            System.out.println("after后置通知");
        }
        //around环绕通知
        public Object around(ProceedingJoinPoint point)throws Throwable{ 
            System.out.println("around环绕通知之前——————");
            Object object = point.proceed();
            System.out.println("around环绕通知之后——————");
            return object;
        }
        //after-returning返回通知
        public void afterReturning(){ 
            System.out.println("after-returning返回通知");
        }
        //after-throwing异常通知
        public void afterThrowing(){ 
            System.out.println("after-throwing异常通知");
        }
    }

配置spring-aop.xml:

<?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 https://www.springframework.org/schema/aop/spring-aop.xsd">
        
        <bean name="userService" class="cn.wqk.service.UserServiceImpl"/>
        <bean name="aspect" class="cn.wqk.aop.Aspect"/>
        
        <aop:config>
            
            <aop:pointcut id="pointcut" expression="execution(* cn.wqk.service.UserServiceImpl.*(..))"/>
            
            <aop:aspect id="aspect" ref="aspect" order="0">
                
                <aop:before method="before" pointcut-ref="pointcut"/>
                
                <aop:after method="after" pointcut-ref="pointcut"/>
                
                <aop:around method="around" pointcut-ref="pointcut"/>
                
                <aop:after-returning method="afterReturning" pointcut-ref="pointcut"/>
                
                <aop:after-throwing method="afterThrowing" pointcut-ref="pointcut"/>
            </aop:aspect>
        </aop:config>
    </beans>

只需要在`<aop:aspect>`里添加order属性，值为数字就行了，同样是数字越小，切面优先级越高。