spring-aop实现

╰半夏微凉° 2022-02-17 05:31 172阅读 0赞

aop介绍  
 AOP（Aspect Oriented Programming）,即面向切面编程，可以说是OOP（Object Oriented Programming，面向对象编程）的补充和完善。  
  面向切面是面向对象中的一种方式而已。在代码执行过程中，动态嵌入其他代码，叫做面向切面编程。常见的使用场景：  
i ：日志  
ii： 事务  
iii：数据库操作

aop的实现方式(schema)

前置通知(MethodBeforeAdvice)

@Component  
public class MyBeforeAdvice implements MethodBeforeAdvice\{

@Override
    public void before(Method method, Object[] args, Object target) throws Throwable {
     System.out.println("前置通知执行:"+method.getName());
    	
    }

后置通知(AfterReturningAdvice)

@Component  
public class AfterAdvice implements AfterReturningAdvice\{

@Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
     System.out.println("后置通知 :"+returnValue);
    	
    }

环绕通知(MethodInterceptor)

@Component  
public class AroundInterceptor implements MethodInterceptor\{

@Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
    	 System.out.println("环绕通知执行1");
    	String msg  = (String)invocation.proceed();
    	 System.out.println("环绕通知执行2");
    	return msg==null?null:msg.toUpperCase();
    }

\}  
异常处理通知(ThrowsAdvice)

@Component  
public class MyThrowsAdvice implements ThrowsAdvice \{

public void afterThrowing(Exception ex){
    	System.out.println("异常参数了:"+ex.getMessage());
    }

测试类

public class Test \{  
public static void main(String\[\] args) \{  
ApplicationContext ac = new ClassPathXmlApplicationContext(“applicationContext.xml”);  
IWindow window = ac.getBean(“mytarget”,IWindow.class);  
window.say();  
System.out.println("----------");  
System.out.println(window.doSome());  
\}  
\}

applicationContext.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>

<context:component-scan base-package=“com.sxt.\*”></context:component-scan>

<bean class="com.sxt.advice.MyBeforeAdvice" id="methodBeforeAdvice"/> 
     <bean class="com.sxt.advice.AfterAdvice" id="afterAdvice"></bean>
     <bean class="com.sxt.advice.AroundInterceptor" id="around"></bean>
     <bean class="com.sxt.advice.MyThrowsAdvice" id="myThrowsAdvice"></bean> 
     <bean class="org.springframework.aop.framework.ProxyFactoryBean" id="mytarget">
    	<property name="target" ref="window" />
    	<property name="interfaces" value="com.sxt.pojo.IWindow" />
    	<property name="interceptorNames">
    		<array>
    			
    			<value>methodBeforeAdvice</value>
    			<value>afterAdvice</value>
    			<value>aroundInterceptor</value>
    			<value>myThrowsAdvice</value>
    		</array>
    	</property>
    </bean>

基于aspectJ方式实现

对于AOP这种编程思想，很多框架都进行了实现。Spring就是其中之一，可以完成面向切面编程。然而，AspectJ也实现了AOP的功能，且其实现方式更为简捷，使用更为方便，而且还支持注解式开发。所以，Spring又将AspectJ的对于AOP的实现也引入到了自己的框架中。在Spring中使用AOP开发时，一般使用AspectJ的实现方式

介绍下xml配置的方式 ,注解的很简单就不发了

实体类

public class Window implements IWindow\{

@Override
    public void say(){
    	System.out.println("div  dir");
    }
    
    @Override
    public String doSome(){
    	System.out.println("你好");
    	
    	return "hello";
    }

切面类

public class Advice\{

public void before(){
    	  System.out.println("前置通知");
      }
    
     
      public void afterReturning(){
    	  System.out.println("后置通知");
      }
      
     
      public Object around(ProceedingJoinPoint pjp) throws Throwable{
    	  System.out.println("环绕通知1");
    	  Object msg = pjp.proceed();
    	  if (msg != null) {
    		msg = msg.toString().toUpperCase();
    		  System.out.println("环绕通知2");
    		return msg;
    	}
    	  return null;
      }
      
      
      
      public void throwing(Exception ex){
    	  System.out.println("参数异常了:"+ex.getMessage());
      }
      
     
      public void after(){
    	  System.out.println("最终通知");
      }

测试类

public class Test \{  
public static void main(String\[\] args) \{  
ApplicationContext ac = new ClassPathXmlApplicationContext(“applicationContext.xml”);  
IWindow window = ac.getBean(IWindow.class);  
window.say();  
System.out.println("----------");  
System.out.println(window.doSome());  
\}  
\}

xml配置文件

<?xml version="1.0" encoding="UTF-8"?>

<aop:config>
    
    	<aop:aspect ref="myAdvice">
    		
    		<aop:pointcut expression="execution(* com.sxt.pojo.*.*(..))" id="pointcut"/>
    		
    		<aop:after-returning method="afterReturning" pointcut-ref="pointcut"/>	
    		<aop:before method="before" pointcut-ref="pointcut"/>	
    		<aop:around method="around" pointcut-ref="pointcut"/>	
    		<aop:after-throwing method="throwing" pointcut-ref="pointcut" throwing="ex"/>	
    		<aop:after method="after" pointcut-ref="pointcut"/>	
    	</aop:aspect>
    </aop:config>

控制台输入  
![在这里插入图片描述][20190418214846117.png]

[20190418214846117.png]: /images/20220217/bd24403cea004366b2e3ce8ac74f98f8.png