spring aof

1、使用SpringAOP完成简单的程序

1.导入SpringAOP所需jar包

2.编写spring的配置文件applicationContext.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"
    
    xsi:schemaLocation="http://www.springframework.org/schema/beans  
        http://www.springframework.org/schema/beans/spring-beans.xsd 
        http://www.springframework.org/schema/util 
        http://www.springframework.org/schema/util/spring-util-4.0.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
        "
        xmlns:util="http://www.springframework.org/schema/util"
        xmlns:p="http://www.springframework.org/schema/p"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop"    
        >
    <!-- configure the package for spring to scan -->
    <context:component-scan base-package="test.Spring.AOP" />
    
    <!-- make the aspectj annotation to be used -->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>

3.创建一个HelloWord接口以及它的实现类HelloWordImpl

public interface HelloWord {
    public int sayHello(int num);
}

@Component
public class HelloWordImpl implements HelloWord{
    public int sayHello(int num){
        System.out.println("hello word");
        return 100/num;
    }
}

4.SpringAOP注释的类型有5种

@Before 前置通知 在方法执行前执行

@After 后置通知 在方法执行后执行

@AfterThrowing 异常通知 在方法抛出异常之后执行

@AfterReturning 返回通知 在方法返回结果之后执行

@Around 环绕通知 环绕着方法执行

5.创建一个切面类（包含@Before @After @AfterThrowing @AfterReturning）

@Component
@Aspect
public class HelloWordAspect {
    
    @Before(value="execution(* test.Spring.AOP.HelloWord.sayHello(..))")
    public void beforeMethod(JoinPoint jp){
        String methodName = jp.getSignature().getName();
        System.out.println(methodName);
        System.out.println("before method execute,args are "+Arrays.toString(jp.getArgs()));
    }

    @After("execution(* test.Spring.AOP.HelloWord.sayHello(..))")
    public void afterMethod(JoinPoint jp){
        System.out.println("after method execute,args are "+Arrays.toString(jp.getArgs()));
    }
    
    @AfterThrowing(value="execution(* test.Spring.AOP.HelloWord.sayHello(..))",throwing="ex")
    public void afterThrow(Exception ex){
        System.out.println("afterThrow"+ex.getMessage());    
    }
    
    @AfterReturning(value="execution(* test.Spring.AOP.HelloWord.sayHello(..))",returning="result")
    public void afterReturn(Object result){
        System.out.println("the result is "+result);
    }
}

6.在主函数调用

public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContextForAOP.xml");
        
        HelloWord hw = (HelloWord) context.getBean("helloWordImpl");
        hw.sayHello(10);
    }
}

7.调用结果

结果说明，在sayHello方法是被Spring代理执行了，执行前后加上了一些切面类中定义的信息。

8.使用Around环绕通知切面类实现类似效果

 

@Component
@Aspect
public class HelloWordAspectAround {
    @Around(value="execution(* test.Spring.AOP.HelloWord.sayHello(..)))")
    public Object aroundMethod(ProceedingJoinPoint pjp){
        Object result = null;
        String methodName = pjp.getSignature().getName();
        try {
            result = pjp.proceed();        
            System.out.println("the result is "+result);
        } catch (Throwable e) {
            System.out.println("Exception occurs : "+e.getMessage());
            throw new RuntimeException(e);
        }
        System.out.println(methodName+" end");
        
        return result;
    }
}