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Spring初学之annotation实现AOP前置通知和后置通知
实现两个整数的加减乘除,并在每个计算前后打印出日志。
ArithmeticCalculator.java:
package spring.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); }
ArithmeticCalculatorImpl.java:
package spring.aop.impl; import org.springframework.stereotype.Component; @Component("arithmeticCalculator") public class ArithmeticCalculatorImpl implements ArithmeticCalculator { public int add(int i, int j) { int result = i+j; return result; } public int sub(int i, int j) { int result = i-j; return result; } public int mul(int i, int j) { int result = i*j; return result; } public int div(int i, int j) { int result = i/j; return result; } }
LoggingAspect.java:
package spring.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:1.把该类放入到IOC容器中,2.再声明一个切面 @Aspect @Component public class LoggingAspect { //声明该方法是一个前置通知:在目标方法之前执行 @Before("execution( public int spring.aop.impl.*.*(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"+args); } //后置通知:在目标方法执行后执行(无论是否发生异常),的通知。 //在后置通知中不能访问目标方法的执行结果 @After("execution( public int spring.aop.impl.*.*(int,int) )") public void afterMethod(JoinPoint joinPoint){ String methodName=joinPoint.getSignature().getName(); System.out.println("The method "+methodName+" ends"); } }
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" 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"> <!-- 配置自动扫描的包 --> <context:component-scan base-package="spring.aop.impl" /> <!-- 使AspectJ注解起作用,自动为匹配的类生成代理对象 --> <aop:aspectj-autoproxy></aop:aspectj-autoproxy> </beans>
测试:
package spring.aop.impl.test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import spring.aop.impl.ArithmeticCalculator; public class Main { public static void main(String[] args) { //1.创建spring的IOC容器 ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml"); //2.从容器中获取bean的实例 ArithmeticCalculator arithmeticCalculator=(ArithmeticCalculator) ctx.getBean("arithmeticCalculator"); //3.使用bean int result = arithmeticCalculator.add(5, 8); System.out.println("result:"+result); result = arithmeticCalculator.div(5, 8); System.out.println("result:"+result); } }
输出:
The method add begins[5, 8] The method add ends result:13 The method div begins[5, 8] The method div ends result:0
Spring初学之annotation实现AOP前置通知和后置通知
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