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方法实现接口
package com.cn.spring.aop.impl; //加减乘除的接口类 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); }
接口实现类
package com.cn.spring.aop.impl; import org.springframework.stereotype.Component; //实现类 @Component public class ArithmeticCalculatorImpl implements ArithmeticCalculator { @Override public int add(int i, int j) { int result = i + j; return result; } @Override public int sub(int i, int j) { int result = i - j; return result; } @Override public int mul(int i, int j) { int result = i * j; return result; } @Override public int div(int i, int j) { int result = i / j; return result; } }
xml文件配置
<?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.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="com.cn.spring.aop.impl"> </context:component-scan> <!--使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>
通知切面
package com.cn.spring.aop.impl; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.ProceedingJoinPoint; 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.springframework.stereotype.Component; import java.util.Arrays; import java.util.List; //把这个类声明为一个切面:首先需要把该类放入到IOC容器中,在声明为一个切面 @Aspect @Component public class LoggingAspect {
@Pointcut("execution(** ArithmeticCalculator.*(..))")
public void declareJointPointExpression(){
}
//声明该方法是一个前置通知:在目标方法开始之前执行
//@Before("execution(public int ArithmeticCalculator.*(int, int))")
//前置通知
@Before("declareJointPointExpression()")
public void beforeMethod(JoinPoint joinPoint) {
String methodName = joinPoint.getSignature().getName();
List<Object> args = Arrays.asList(joinPoint.getArgs());
Object target = joinPoint.getTarget();
System.out.println("The method " + methodName + " begins with " + args + target);
}
//后置通知 @After("execution(** ArithmeticCalculator.*(int, int))") public void afterMethod(JoinPoint joinPoint){ String methodName = joinPoint.getSignature().getName(); System.out.println("The method " + methodName + " ends "); } //返回通知,在方法正常结束后执行的方法,可以访问到方法的返回值 @AfterReturning(value="execution(** ArithmeticCalculator.*(int, int))", 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 @AfterThrowing(value="execution(** ArithmeticCalculator.*(int, int))", throwing = "ex") public void afterThrowing(Exception ex){ System.out.println(ex); } } /* * JoinPoint访问到连接点上下文的信息 * JoinPoint ? java.lang.Object[] getArgs():获取连接点方法运行时的入参列表; ? Signature getSignature() :获取连接点的方法签名对象; ? java.lang.Object getTarget() :获取连接点所在的目标对象; ? java.lang.Object getThis() :获取代理对象本身; * */
环绕通知类似于动态代理的全过程
如果环绕通知返回100,则结果为100
//功能最强大的环绕通知 //ProceedingJoinPoint 类型的参数可以决定是否执行目标方法 @Around("execution(** ArithmeticCalculator.*(..))") public Object aroundMethod(ProceedingJoinPoint pjd){ Object result = null ; String methodName = pjd.getSignature().getName(); try { System.out.println("before"); result = pjd.proceed(); System.out.println("after " + result); } catch (Throwable e) { // TODO Auto-generated catch block e.printStackTrace(); System.out.println("Exception " + e); } System.out.println("return " + result); return result; }
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原文地址:http://www.cnblogs.com/da-peng/p/5939695.html