后置通知
看代码:
package logan.study.aop.impl; public interface ArithmeticCalculator { int add(int i, int j); int sub(int i, int j); int mul(int i, int j); int div(int i, int j); }
package logan.study.aop.impl; import org.springframework.stereotype.Component; @Component public class ArithmeticCalculatorImpl implements ArithmeticCalculator { @Override public int add(int i, int j) { // TODO Auto-generated method stub int result = i + j; return result; } @Override public int sub(int i, int j) { // TODO Auto-generated method stub int result = i - j; return result; } @Override public int mul(int i, int j) { // TODO Auto-generated method stub int result = i * j; return result; } @Override public int div(int i, int j) { // TODO Auto-generated method stub int result = i / j; return result; } }
package logan.study.aop.impl; import java.util.Arrays; import java.util.List; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.After; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.springframework.stereotype.Component; //把这个类声明为一个切面:需要把该类放入到IOC容器中,在声明为一个切面 @Aspect @Component public class LoggingAspect { //声明该方法时一个前置通知:在目标方法开始之前执行 @Before("execution(public int logan.study.aop.impl.ArithmeticCalculator.*(int, int))") public void beforeMethod(JoinPoint joinPoint){ String methodName = joinPoint.getSignature().getName(); List<Object> args = Arrays.asList(joinPoint.getArgs()); System.out.println("The method "+ methodName +" begins with "+args); } //后置通知,在目标方法执行之后执行(无论该方法是否出现异常) //在后置通知中,还不能访问目标方法执行的结果,执行结果在返回通知中可以访问 @After("execution(public int logan.study.aop.impl.ArithmeticCalculator.*(int, int))") public void afterMethod(JoinPoint joinPoint){ String methodName = joinPoint.getSignature().getName(); List<Object> args = Arrays.asList(joinPoint.getArgs()); System.out.println("The method "+ methodName +" ends with "+args); } }
<?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:context="http://www.springframework.org/schema/context" 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/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd"> <context:component-scan base-package="logan.study.aop.impl"></context:component-scan> <aop:aspectj-autoproxy></aop:aspectj-autoproxy> </beans>
package logan.study.aop.impl; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) { // TODO Auto-generated method stub //1.创建Spring的IOC容器 ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); //2.从IOC容器里面获取bean实例 ArithmeticCalculator arithmeticCalculator = ctx.getBean(ArithmeticCalculator.class); //使用Bean int result = arithmeticCalculator.add(3, 6); System.out.println(result); result = arithmeticCalculator.div(3, 6); System.out.println(result); } }
输出结果:
五月 27, 2017 5:46:24 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@49c2faae: startup date [Sat May 27 17:46:24 CST 2017]; root of context hierarchy 五月 27, 2017 5:46:24 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [applicationContext.xml] The method add begins with [3, 6] The method add ends with [3, 6] 9 The method div begins with [3, 6] The method div ends with [3, 6] 0