spring-重用切点表达式

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