package com.spring.aop.impl;
public interface ArithmeticCalculator {
public int add(int i, int j);
public int sub(int i, int j);
public int mul(int i, int j);
public int div(int i, int j);
}
接口实现类 ArithmeticCalculatorImpl.java
package com.spring.aop.impl;
import org.springframework.stereotype.Component;
@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;
}
}
切面类 LoggingAspect.java
package com.spring.aop.impl;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
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.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
//把这个类声明为一个切面：需要把该类放入到IOC容器中。再声明为一个切面.
@Aspect
@Component
public class LoggingAspect {
/**
*前置通知，在目标方法开始之前执行。
*@Before("execution(public int com.spring.aop.impl.ArithmeticCalculator.add(int, int))")这样写可以指定特定的方法。
* @param joinpoint
*/
@Before("execution(public int com.spring.aop.impl.ArithmeticCalculator.*(int, int))")
public void beforeMethod(JoinPoint joinpoint) {
String methodName = joinpoint.getSignature().getName();
List<Object>args = Arrays.asList(joinpoint.getArgs());
System.out.println("前置通知：The method "+ methodName +" begins with " + args);
}
/**
*后置通知，在目标方法执行之后开始执行，无论目标方法是否抛出异常。
*在后置通知中不能访问目标方法执行的结果。
* @param joinpoint
*/
@After("execution(public int com.spring.aop.impl.ArithmeticCalculator.*(int, int))")
public void afterMethod(JoinPoint joinpoint) {
String methodName = joinpoint.getSignature().getName();
//List<Object>args = Arrays.asList(joinpoint.getArgs()); 后置通知方法中可以获取到参数
System.out.println("后置通知：The method "+ methodName +" ends ");
}
/**
*返回通知，在方法正常结束之后执行。
*可以访问到方法的返回值。
* @param joinpoint
* @param result 目标方法的返回值
*/
@AfterReturning(value="execution(public int com.spring.aop.impl.ArithmeticCalculator.*(..))", returning="result")
public void afterReturnning(JoinPoint joinpoint, Object result) {
String methodName = joinpoint.getSignature().getName();
System.out.println("返回通知：The method "+ methodName +" ends with " + result);
}
/**
*异常通知。目标方法出现异常的时候执行，可以访问到异常对象，可以指定在出现特定异常时才执行。
*假如把参数写成NullPointerException则只在出现空指针异常的时候执行。
* @param joinpoint
* @param e
*/
@AfterThrowing(value="execution(public int com.spring.aop.impl.ArithmeticCalculator.*(..))", throwing="e")
public void afterThrowing(JoinPoint joinpoint, Exception e) {
String methodName = joinpoint.getSignature().getName();
System.out.println("返回通知：The method "+ methodName +" occurs exception " + e);
}
/**
* 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。
* @param point 环绕通知需要携带ProceedingJoinPoint类型的参数。
* @return 目标方法的返回值。必须有返回值。
*/
/*不常用
@Around("execution(public int com.spring.aop.impl.ArithmeticCalculator.*(..))")
public Object aroundMethod(ProceedingJoinPoint point) {
Object result = null;
String methodName = point.getSignature().getName();
try {
//前置通知
System.out.println("The method "+ methodName +" begins with " + Arrays.asList(point.getArgs()));
//执行目标方法
result = point.proceed();
//翻译通知
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;
}
*/
}
applicationContext.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-4.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd">
<!-- 配置自动扫描包 -->
<context:component-scan base-package="com.spring.aop.impl"></context:component-scan>
<!-- 使AspectJ注解起作用：自动为匹配的类生产代理对象 -->
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>
Main.java
package com.spring.aop.impl;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
public static void main(String[] args) {
//创建spring IOC容器
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
//从IOC容器中获取bean实例
ArithmeticCalculator arithmeticCalculator = applicationContext.getBean(ArithmeticCalculator.class);
int result = arithmeticCalculator.add(4, 6);
System.out.println(result);
result = arithmeticCalculator.sub(4, 6);
System.out.println(result);
System.out.println(result);
result = arithmeticCalculator.mul(4, 6);
System.out.println(result);
System.out.println(result);
result = arithmeticCalculator.div(4, 0);
System.out.println(result);
}
}