Spring 使用 AspectJ 进行 AOP 的开发

1）引入相关的jar包

• spring 的传统 AOP 的开发的包：
  spring-aop-4.2.4.RELEASE.jar
  com.springsource.org.aopalliance-1.0.0.jar
• aspectJ 的开发包:
  com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar
  spring-aspects-4.2.4.RELEASE.jar
  

2）引入Spring的配置文件

引入 AOP 约束:
<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">
</beans>

3）编写目标类

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

    public void update() {
        System.out.println("修改商品...");
    }

    public void delete() {
        System.out.println("删除商品...");
    }

    public void find() {
        System.out.println("查询商品...");
    }
}

4）配置目标类

<bean id="productDao" class="cn.itcast.spring.demo4.ProductDao"></bean>

5）开启aop注解的自动代理

<aop:aspectj-autoproxy/>

6）AspectJ的AOP的注解

@Aspect:定义切面类的注解

通知类型:

• @Before :前置通知
• @AfterReturing :后置通知
• @Around :环绕通知
• @After :最终通知
• @AfterThrowing :异常抛出通知.
• @Pointcut:定义切入点的注解

7）编写切面类

@Aspect
public class MyAspectAnno {
    
    @Before("MyAspectAnno.pointcut1()")
    public void before() {
        System.out.println("前置通知===========");
    }

    @Pointcut("execution(* cn.itcast.spring.demo4.ProductDao.save(..))")
    private void pointcut1() {
    }
}

8）配置切面

<!-- 配置切面类 -->
<bean id="myAspectAnno" class="cn.itcast.spring.demo4.MyAspectAnno"></bean>

9）其它通知的注解

@Aspect
public class MyAspectAnno {
    @Before("MyAspectAnno.pointcut1()")
    public void before() {
        System.out.println("前置通知===========");
    }

    @AfterReturning("MyAspectAnno.pointcut2()")
    public void afterReturning() {
        System.out.println("后置通知===========");
    }

    @Around("MyAspectAnno.pointcut3()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("环绕前通知==========");
        Object obj = joinPoint.proceed();
        System.out.println("环绕后通知==========");
        return obj;
    }

    @AfterThrowing("MyAspectAnno.pointcut4()")
    public void afterThrowing() {
        System.out.println("异常抛出通知========");
    }

    @After("MyAspectAnno.pointcut4()")
    public void after() {
        System.out.println("最终通知==========");
    }

    @Pointcut("execution(* cn.itcast.spring.demo4.ProductDao.save(..))")
    private void pointcut1() {
    }

    @Pointcut("execution(* cn.itcast.spring.demo4.ProductDao.update(..))")
    private void pointcut2() {
    }

    @Pointcut("execution(* cn.itcast.spring.demo4.ProductDao.delete(..))")
    private void pointcut3() {
    }

    @Pointcut("execution(* cn.itcast.spring.demo4.ProductDao.find(..))")
    private void pointcut4() {
    }
}