介绍spring重用切点表达式
关键带代码:
@Aspect @Component public class LogAspect { // 使用@Pointcut定义一个方法,用于声切入点明表达式,这个方法一般不需要加入其它代码 @Pointcut("execution(public double com.shuoeasy.test.ArithmeticCalculator.add(double, double))") public void declareJointPointExpression1(){} // 使用方法名来引用切入点表达式 @After("declareJointPointExpression1()") public void alterMethod(JoinPoint joinPoint){ System.out.println("日志-后置通知"); } }
详细:
ArithmeticCalculator.java:
package com.shuoeasy.test; /** * 定义计算器接口 * */ public interface ArithmeticCalculator { double add(double num1, double num2); double sub(double num1, double num2); double mul(double num1, double num2); double div(int num1, int num2); }
ArithmeticCalculatorImpl.java:
package com.shuoeasy.test; import org.springframework.stereotype.Component; /** * 业务类 */ @Component("arithmeticCalculator") public class ArithmeticCalculatorImpl implements ArithmeticCalculator{ public double add(double num1, double num2) { double result = num1 + num2; return result; } public double sub(double num1, double num2) { double result = num1 - num2; return result; } public double mul(double num1, double num2) { double result = num1 * num2; return result; } public double div(int num1, int num2) { double result = num1 / num2; return result; } }
LogAspect.java:
package com.shuoeasy.test; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.After; import org.aspectj.lang.annotation.AfterReturning; import org.aspectj.lang.annotation.AfterThrowing; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; import org.springframework.stereotype.Component; @Aspect @Component public class LogAspect { // 使用@Pointcut定义一个方法,用于声切入点明表达式,这个方法一般不需要加入其它代码 @Pointcut("execution(public double com.shuoeasy.test.ArithmeticCalculator.add(double, double))") public void declareJointPointExpression1(){} @Pointcut("execution(* com.shuoeasy.test.*.*(..))") public void declareJointPointExpression2(){} // 使用方法名来引用切入点表达式 @Before("declareJointPointExpression1()") public void beforeMethod(JoinPoint joinPoint){ System.out.println("日志-前置通知"); } @After("declareJointPointExpression1()") public void alterMethod(JoinPoint joinPoint){ System.out.println("日志-后置通知"); } @AfterReturning(value="declareJointPointExpression2()",returning="result") public void afterReturning(JoinPoint joinPoint, Object result){ System.out.println("日志-返回通知"); } @AfterThrowing(value="declareJointPointExpression2()",throwing="ex") public void afterThrowing(JoinPoint joinPoint, Exception ex){ System.out.println("日志-异常通知"); } }
VerificationAspect.java:
package com.shuoeasy.test; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.springframework.core.annotation.Order; import org.springframework.stereotype.Component; @Order(1) //数字越小优先级越高 @Aspect @Component // 验证类 public class VerificationAspect { // 跨类引用切入点表达式 @Before("LogAspect.declareJointPointExpression2()") public void beforeMethod(JoinPoint joinPoint){ System.out.println("验证-前置通知"); } }
bean.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:p="http://www.springframework.org/schema/p" 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-4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd"> <!-- 自动扫描的包 --> <context:component-scan base-package="com.shuoeasy.test"></context:component-scan> <!-- 使用Aspjectj 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>
Main.xml:
package com.shuoeasy.test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) { // 1.创建spring的IOC容器 ApplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml"); // 2.从IOC容器中获取bean的实例 ArithmeticCalculator arithmeticCalulator = (ArithmeticCalculator)ctx.getBean("arithmeticCalculator"); // 3.使用bean double result = arithmeticCalulator.add(2, 3); System.out.println("result=" + result); } }
输出:
验证-前置通知 日志-前置通知 result=5.0