Spring AOP examples of development based Aspectj comments

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Aspectj common comment

 - 1、@Before 前置通知，相当于BeforeAdvice

        ps:在目标方法之前执行
        应用场景：如在保存之前进行权限校验，只有管理员身份才有权限保存；
 

 - 2、@AfterReturning 后置通知，相当于AfterReturningAdvice

        ps:在目标方法之后执行
        应用场景：如在删除一条记录时候，记录是谁什么时候删除的；

 - 3、@Around 环绕通知，相当于MethodInterceptor

        ps:在目标方法之前和之后执行，可以阻止目标方法执行
        应用场景：如事务处理，在目标方法之前开启事务，目标方法之后提交或回滚事务；

 - 4、@AfterThrowing 异常抛出通知，相当于ThrowAdvice

        ps：只会在目标方法有异常的情况下，才会执行

 - 5、@After 最终final通知

     不管是否有异常，该通知都会执行；

In the notification attribute value is defined by the point of tangency

In the notification attribute value is defined by the point of tangency

• The execution function, you can define the cut point cut method

• Syntax:
-execution (<access modifier> <return type> <method name> (<parameter>) <Exceptions>?)

•E.g

• - class matches all public methods execution (public * * (...))

• - all packets matching the specified class method under execution (* com.imooc.dao * (...).)

• - the sub-packets do not contain -execution (* com.imooc.dao ... * (...)) ... * denotes the package, the package and all descendants of the class

• - all methods that match the specified class execution (* com.imooc.service.UserService * (...).)

• - all classes implement a specific interface matching method execution (* com.imooc.dao.GenericDAO + * (...).)

• - method for matching save all begin with the execution (* save * (...))

Code

ProductDao.java

package com.shunli.aspect.demo1;

public class ProductDao {
    public void save(){
        System.out.println("save......");
    }

    public String  update(){
        System.out.println("update......");
        return "update return";
    }

    public void find(){
        System.out.println("find......");

    }

    public void findAll(){
        System.out.println("findAll......");
    }

    public void delete(){
        System.out.println("delete......");
        int i = 1/0;//异常
    }
}

MyAspectAnno.java

package com.shunli.aspect.demo1;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;

/**
 * @author shunli
 * 切面类
 */
@Aspect
public class MyAspectAnno {

    //设置save方法为前置通知
    @Before(value = "execution(* com.shunli.aspect.demo1.ProductDao.save(..))")
    public void before(JoinPoint joinPoint){
        System.out.println("前置通知......" + joinPoint);
    }

    //设置update方法为后置通知
    @AfterReturning(value = "execution(* com.shunli.aspect.demo1.ProductDao.update(..))", returning = "result")
    public void afterReturing(Object result){
        System.out.println("后置通知=================="+result);
    }

    //设置find方法为环绕通知
    @Around(value = "execution(* com.shunli.aspect.demo1.ProductDao.find(..))")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("环绕前通知================");
        // 执行目标方法
        Object obj = joinPoint.proceed();
        System.out.println("环绕后通知================");
        return obj;
    }

    //设置findAll为最终通知
    @After(value = "execution(* com.shunli.aspect.demo1.ProductDao.findAll(..))")
    public void after(){
        System.out.println("最终通知==================");
    }

    //设置delete方法为异常抛出通知
    @AfterThrowing(value = "myPointcut()", throwing = "e")
    public void afterThrowing (Throwable e){
        System.out.println("异常抛出通知==============" + e.getMessage());
    }

    //上面的value也可以用myPointcut代替
    @Pointcut(value="execution(* com.shunli.aspect.demo1.ProductDao.delete(..))")
    private void myPointcut(){}

}

applictionContext.xml configure

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

    <!--开启aspectj注解开发  自动代理-->
    <aop:aspectj-autoproxy/>

    <!--目标类-->
    <bean id="productDao" class="com.shunli.aspect.demo1.ProductDao"/>

    <!--定义切面-->
    <bean class="com.shunli.aspect.demo1.MyAspectAnno"/>
    
</beans>

SpringDemo1.java in

package com.shunli.aspect.demo1;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applictionContext.xml")
public class SpringDemo1 {

    @Resource(name = "productDao")
    private  ProductDao productDao;

    @Test
    public void demo1(){
        productDao.save();
        productDao.update();
        productDao.find();
        productDao.findAll();
        productDao.delete();
    }
}

Output