基于注解的方式实现通知

1.需要的jar包：

com.springsource.net.sf.cglib-2.2.0.jar
com.springsource.org.aopalliance-1.0.0.jar
com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar
commons-logging-1.1.1.jar
spring-aop-4.0.0.RELEASE.jar
spring-aspects-4.0.0.RELEASE.jar
spring-beans-4.0.0.RELEASE.jar
spring-context-4.0.0.RELEASE.jar
spring-core-4.0.0.RELEASE.jar
spring-expression-4.0.0.RELEASE.jar

2.实现类：

注意：由于是使用注解的方式所以需要在实现类中添加注解

如下：

package com.atguigu.spring.aop;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 com.atguigu.spring.aop;import org.springframework.stereotype.Component;@Component("arithmeticCalculator")
public class ArithmeticCalculatorImpl implements ArithmeticCalculator {@Overridepublic int add(int i, int j) {int result = i + j;return result;}@Overridepublic int sub(int i, int j) {int result = i - j;return result;}@Overridepublic int mul(int i, int j) {int result = i * j;return result;}@Overridepublic int div(int i, int j) {int result = i / j;return result;}}

3.配置文件：

<?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:aop="http://www.springframework.org/schema/aop"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- 自动扫描的包 --><context:component-scan base-package="com.atguigu.spring.aop"></context:component-scan><!-- 使 AspectJ 的注解起作用 --><aop:aspectj-autoproxy></aop:aspectj-autoproxy></beans>

4.通知切面（1）：

import java.util.Arrays;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;/*** AOP 的 helloWorld* 1. 加入 jar 包* com.springsource.net.sf.cglib-2.2.0.jar* com.springsource.org.aopalliance-1.0.0.jar* com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar* spring-aspects-4.0.0.RELEASE.jar* * 2. 在 Spring 的配置文件中加入 aop 的命名空间。 * * 3. 基于注解的方式来使用 AOP* 3.1 在配置文件中配置自动扫描的包: <context:component-scan base-package="com.atguigu.spring.aop"></context:component-scan>* 3.2 加入使 AspjectJ 注解起作用的配置: <aop:aspectj-autoproxy></aop:aspectj-autoproxy>* 为匹配的类自动生成动态代理对象. * * 4. 编写切面类: * 4.1 一个一般的 Java 类* 4.2 在其中添加要额外实现的功能. ** 5. 配置切面* 5.1 切面必须是 IOC 中的 bean: 实际添加了 @Component 注解* 5.2 声明是一个切面: 添加 @Aspect* 5.3 声明通知: 即额外加入功能对应的方法. * 5.3.1 前置通知: @Before("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(int, int))")* @Before 表示在目标方法执行之前执行 @Before 标记的方法的方法体. * @Before 里面的是切入点表达式: * * 6. 在通知中访问连接细节: 可以在通知方法中添加 JoinPoint 类型的参数, 从中可以访问到方法的签名和方法的参数. * * 7. @After 表示后置通知: 在方法执行之后执行的代码. *///通过添加 @Aspect 注解声明一个 bean 是一个切面!
@Aspect
@Component
public class LoggingAspect {@Before("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(int, int))")public void beforeMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();Object [] args = joinPoint.getArgs();System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));}@After("execution(* com.atguigu.spring.aop.*.*(..))")public void afterMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends");}}

5.测试实现1：

package com.atguigu.spring.aop;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-aop.xml");ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");System.out.println(arithmeticCalculator.getClass().getName());int result = arithmeticCalculator.add(11, 12);System.out.println("result:" + result);result = arithmeticCalculator.div(21, 3);System.out.println("result:" + result);}}

6.通知切面2及切面优先级：

package com.atguigu.spring.aop;import java.util.Arrays;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.core.annotation.Order;
import org.springframework.stereotype.Component;/*** 可以使用 @Order 注解指定切面的优先级, 值越小优先级越高*/
@Order(2)
@Aspect
@Component
public class LoggingAspect {/*** 定义一个方法, 用于声明切入点表达式. 一般地, 该方法中再不需要添入其他的代码. * 使用 @Pointcut 来声明切入点表达式. * 后面的其他通知直接使用方法名来引用当前的切入点表达式. */@Pointcut("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")public void declareJointPointExpression(){}/*** 在 com.atguigu.spring.aop.ArithmeticCalculator 接口的每一个实现类的每一个方法开始之前执行一段代码*/@Before("declareJointPointExpression()")public void beforeMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();Object [] args = joinPoint.getArgs();System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));}/*** 在方法执行之后执行的代码. 无论该方法是否出现异常*/@After("declareJointPointExpression()")public void afterMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends");}/*** 在方法法正常结束受执行的代码* 返回通知是可以访问到方法的返回值的!*/@AfterReturning(value="declareJointPointExpression()",returning="result")public void afterReturning(JoinPoint joinPoint, Object result){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends with " + result);}/*** 在目标方法出现异常时会执行的代码.* 可以访问到异常对象; 且可以指定在出现特定异常时在执行通知代码*/@AfterThrowing(value="declareJointPointExpression()",throwing="e")public void afterThrowing(JoinPoint joinPoint, Exception e){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " occurs excetion:" + e);}/*** 环绕通知需要携带 ProceedingJoinPoint 类型的参数. * 环绕通知类似于动态代理的全过程: ProceedingJoinPoint 类型的参数可以决定是否执行目标方法.* 且环绕通知必须有返回值, 返回值即为目标方法的返回值*//*@Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")public Object aroundMethod(ProceedingJoinPoint pjd){Object result = null;String methodName = pjd.getSignature().getName();try {//前置通知System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));//执行目标方法result = pjd.proceed();//返回通知System.out.println("The method " + methodName + " ends with " + result);} catch (Throwable e) {//异常通知System.out.println("The method " + methodName + " occurs exception:" + e);throw new RuntimeException(e);}//后置通知System.out.println("The method " + methodName + " ends");return result;}*/
}

package com.atguigu.spring.aop;import java.util.Arrays;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)
@Aspect
@Component
public class VlidationAspect {@Before("com.atguigu.spring.aop.LoggingAspect.declareJointPointExpression()")public void validateArgs(JoinPoint joinPoint){System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));}}

7测试2：

package com.atguigu.spring.aop;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");System.out.println(arithmeticCalculator.getClass().getName());int result = arithmeticCalculator.add(1, 2);System.out.println("result:" + result);result = arithmeticCalculator.div(1000, 10);System.out.println("result:" + result);}}

基于xml文件配置的方式

package com.atguigu.spring.aop.xml;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 com.atguigu.spring.aop.xml;public class ArithmeticCalculatorImpl implements ArithmeticCalculator {@Overridepublic int add(int i, int j) {int result = i + j;return result;}@Overridepublic int sub(int i, int j) {int result = i - j;return result;}@Overridepublic int mul(int i, int j) {int result = i * j;return result;}@Overridepublic int div(int i, int j) {int result = i / j;return result;}}package com.atguigu.spring.aop.xml;import java.util.Arrays;import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;public class LoggingAspect {public void beforeMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();Object [] args = joinPoint.getArgs();System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));}public void afterMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends");}public void afterReturning(JoinPoint joinPoint, Object result){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends with " + result);}public void afterThrowing(JoinPoint joinPoint, Exception e){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " occurs excetion:" + e);}@Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")public Object aroundMethod(ProceedingJoinPoint pjd){Object result = null;String methodName = pjd.getSignature().getName();try {//前置通知System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));//执行目标方法result = pjd.proceed();//返回通知System.out.println("The method " + methodName + " ends with " + result);} catch (Throwable e) {//异常通知System.out.println("The method " + methodName + " occurs exception:" + e);throw new RuntimeException(e);}//后置通知System.out.println("The method " + methodName + " ends");return result;}
}package com.atguigu.spring.aop.xml;import java.util.Arrays;import org.aspectj.lang.JoinPoint;public class VlidationAspect {public void validateArgs(JoinPoint joinPoint){System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));}}package com.atguigu.spring.aop.xml;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-xml.xml");ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");System.out.println(arithmeticCalculator.getClass().getName());int result = arithmeticCalculator.add(1, 2);System.out.println("result:" + result);result = arithmeticCalculator.div(1000, 0);System.out.println("result:" + result);}}

<?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:aop="http://www.springframework.org/schema/aop"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd"><!-- 配置 bean --><bean id="arithmeticCalculator" class="com.atguigu.spring.aop.xml.ArithmeticCalculatorImpl"></bean><!-- 配置切面的 bean. --><bean id="loggingAspect"class="com.atguigu.spring.aop.xml.LoggingAspect"></bean><bean id="vlidationAspect"class="com.atguigu.spring.aop.xml.VlidationAspect"></bean><!-- 配置 AOP --><aop:config><!-- 配置切点表达式 --><aop:pointcut expression="execution(* com.atguigu.spring.aop.xml.ArithmeticCalculator.*(int, int))" id="pointcut"/><!-- 配置切面及通知 --><aop:aspect ref="loggingAspect" order="2"><aop:before method="beforeMethod" pointcut-ref="pointcut"/><aop:after method="afterMethod" pointcut-ref="pointcut"/><aop:after-throwing method="afterThrowing" pointcut-ref="pointcut" throwing="e"/><aop:after-returning method="afterReturning" pointcut-ref="pointcut" returning="result"/><!--  <aop:around method="aroundMethod" pointcut-ref="pointcut"/>--></aop:aspect>    <aop:aspect ref="vlidationAspect" order="1"><aop:before method="validateArgs" pointcut-ref="pointcut"/></aop:aspect></aop:config></beans>