注解形式
步骤一、定义一个interface
public interface ArithmeticCalculator { double plus(int i, int j); double sub(int i, int j); double multi(int i, int j); double div(int i, int j); }
步骤二、实现上面的接口
import org.springframework.stereotype.Component; @Component("arithmeticCalculator") public class ArithmeticCalculatorImpl implements ArithmeticCalculator { public double plus(int i, int j) { double result = i + j; return result; } public double sub(int i, int j) { double result = i - j; return result; } public double multi(int i, int j) { double result = i * j; return result; } public double div(int i, int j) { double result = i / j; return result; } }
步骤三、写切面类
import org.aspectj.lang.JoinPoint; import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.annotation.*; import org.springframework.stereotype.Component; import java.util.Arrays; @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(* com.spring2.lee.aop.impl.*.*(..))") public void declareJointPointExpression(){} /** * 前置通知 * 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 * 用通配符*来表示所有 */ // @Before("execution(public double com.spring2.lee.aop.impl.ArithmeticCalculator.plus(int, int))") @Before("declareJointPointExpression()") public void beforeMethod(JoinPoint joinPoint) { String methodName = joinPoint.getSignature().getName(); Object[] args = joinPoint.getArgs(); System.out.println("before method " + methodName + " begin with:" + Arrays.asList(args)); } /** * 后置通知 * 在方法执行之后执行的代码. 无论该方法是否出现异常 * @param joinPoint */ @After("execution(public double com.spring2.lee.aop.impl.*.*(..))") public void afterMethod(JoinPoint joinPoint) { String methodName = joinPoint.getSignature().getName(); Object[] args = joinPoint.getArgs(); System.out.println("after method " + methodName + " end " + Arrays.asList(args)); } /** * 返回通知 * 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 = "execution(public double com.spring2.lee.aop.impl.*.*(..))", returning = "result") public void afterReturning(JoinPoint joinPoint, Object result) { String methodName = joinPoint.getSignature().getName(); System.out.println("The method " + methodName + " ends with " + result); } /** * 异常通知 * 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 = "execution(public double com.spring2.lee.aop.impl.*.*(..))", 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 double com.spring2.lee.aop.impl.*.*(..))") 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; } }
步骤四、测试
import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class MainTest { public static void main(String[] args) { //1.创建Spring 的IOC 容器 ApplicationContext application = new ClassPathXmlApplicationContext("applicationContext.xml"); //2. 从IOC 容器中获取bean 的实例 ArithmeticCalculator arithmeticCalculator = application.getBean(ArithmeticCalculator.class); double result = arithmeticCalculator.div(2,2); //System.out.println("result:" + result); } }
用xml配置的方式实现AOP
Java代码跟上面的一样，只不过注解都没有了，都是用xml来配置bean,所以只粘贴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: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.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> <!-- 配置 bean --> <bean id="arithmeticCalculator" class="com.spring2.lee.aop.impl.ArithmeticCalculatorImpl"></bean> <!-- 配置切面的 bean. --> <bean id="loggingAspect" class="com.spring2.lee.aop.impl.LoggingAspect"></bean> <bean id="vlidationAspect" class="com.spring2.lee.aop.impl.VlidationAspect"></bean> <!-- 配置 AOP --> <aop:config> <!-- 配置切点表达式 --> <aop:pointcut id="pointcut" expression="execution(* com.spring2.lee.aop.impl.ArithmeticCalculator.*(int, int))"/> <!-- 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>
