Spring AOP之AspectJ的注解方式使用

水深无声 2022-07-18 01:50 171阅读 0赞

需要导入的jar包，请看上一篇博客。

注解：

*  如果使用注解进行aop开发，必须进行aspectj自动代理

> > <aop:aspectj-autoproxy>

*  通知注解

> > @Before 前置

> > @AfterReturning 后置

> > @Around 环绕
> 
> > @AfterThrowing 异常
> 
> > @After 最终

*  切面类

> > @Aspect

*   声明切入点

> > @PointCut

（1）TeacherService.java服务接口

package com.itheima.e_aspectj_annotation;
    
    public interface TeacherService {
    	
    	public void addTeacher();
    	public String updateTeacher();
    
    }

（2）TeacherServiceImpl.java实现接口

> 注意要把@Service注解加上。

package com.itheima.e_aspectj_annotation;
    
    import org.springframework.stereotype.Service;
    
    @Service
    public class TeacherServiceImpl implements TeacherService {
    
    	@Override
    	public void addTeacher() {
    		System.out.println("d_aspect anno  add teacher");
    		//int i = 1/0;
    	}
    
    	@Override
    	public String updateTeacher() {
    		System.out.println("d_aspect anno  update teacher");
    		return "来来来";
    	}
    
    }

（3）MyAspect.java类

> 注意注解，声明切面类。

package com.itheima.e_aspectj_annotation;
    
    import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.AfterReturning;
    import org.aspectj.lang.annotation.AfterThrowing;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.stereotype.Component;
    
    /**
     * 切面类，含多个通知
     * @author <a>传智•左慈</a>
     *
     */
    @Component
    @Aspect  //<aop:aspect ref="myAspect">
    public class MyAspect {
    	
    	
    	//@Before("execution(* com.itheima.e_aspectj_annotation.*.*(..))")
    	public void myBefore(JoinPoint joinPoint){
    		System.out.println("前置通知, 方法名称：" + joinPoint.getSignature().getName());
    	}
    	
    	//@AfterReturning(value="execution(* com.itheima.e_aspectj_annotation.*.*(..))",returning="xxx")
    	public void myAfterReturning(JoinPoint joinPoint,Object xxx){
    		System.out.println("后置通知, 返回值：" + xxx);
    	}
    	
    	//@Around("execution(* com.itheima.e_aspectj_annotation.*.*(..))")
    	public Object myAround(ProceedingJoinPoint joinPoint) throws Throwable{
    		
    		System.out.println("前");
    		//必须执行目标方法
    		Object obj = joinPoint.proceed();
    		
    		System.out.println("后");
    		return obj;
    	}
    	
    	//@AfterThrowing(value="execution(* com.itheima.e_aspectj_annotation.*.*(..))" ,throwing="e")
    	public void myAfterThrowing(JoinPoint joinPoint, Throwable e){
    		System.out.println("抛出异常通知, " + e.getMessage());
    	}
    	@After("myPonitCut()")
    	public void myAfter(){
    		System.out.println("最终");
    	}
    	
    	/**
    	 * 使用 @Pointcut 声明切入点表达式，必须修饰在方法：私有，没有返回值，方法名任意
    	 * 在通知中可以通过方法获得，相当于调用方法。
    	 */
    	@Pointcut("execution(* com.itheima.e_aspectj_annotation.*.*(..))")
    	private void myPonitCut(){
    		
    	}
    
    }

（4）beans.xml配置文件

> 实际上只有两个注解有用。
> 
> 1、声明扫描的包

> > <context:component-scan base-package="com.itheima.e\_aspectj\_annotation"></context:component-scan>  
> 
> 2、

> > <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:aop="http://www.springframework.org/schema/aop"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://www.springframework.org/schema/beans 
           					   http://www.springframework.org/schema/beans/spring-beans.xsd
           					   http://www.springframework.org/schema/aop 
           					   http://www.springframework.org/schema/aop/spring-aop.xsd
           					   http://www.springframework.org/schema/context
           					   http://www.springframework.org/schema/context/spring-context.xsd
           					   ">
    	
    	
    	 
    	 <context:component-scan base-package="com.itheima.e_aspectj_annotation"></context:component-scan>
    	 
    	
    	<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
    	
    	
    	
    	
    	
    	
    </beans>

（5）TestApp.java单元测试类

package com.itheima.e_aspectj_annotation;
    
    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:com/itheima/e_aspectj_annotation/beans.xml")
    public class TestApp {
    	
    	@Autowired
    	private TeacherService teacherService;
    	
    	@Test
    	public void demo01(){
    		//获得目标类
    //		String xmlPath = "com/itheima/e_aspectj_annotation/beans.xml";
    //		ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
    //		TeacherService teacherService = (TeacherService) applicationContext.getBean("teacherServiceId");
    		teacherService.addTeacher();
    		teacherService.updateTeacher();
    	}
    
    }