Spring之AOP基于注解配置切面

①新建接口

public interface Cacl {
    
    int add(int i,int j);
    int sub(int i,int j);
    int mul(int i,int j);
    int div(int i,int j);

}

②实现接口

import org.springframework.stereotype.Component;

@Component
public class CaclImpl implements Cacl {

    @Override
    public int add(int i, int j) {
        // TODO Auto-generated method stub
        int result = i+j;
        return result;
    }

    @Override
    public int sub(int i, int j) {
        // TODO Auto-generated method stub
        int result = i-j;
        return result;
    }

    @Override
    public int mul(int i, int j) {
        // TODO Auto-generated method stub
        int result = i*j;
        return result;
    }

    @Override
    public int div(int i, int j) {
        // TODO Auto-generated method stub
        int result = i/j;
        return result;
    }

}

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;

@Aspect
@Component
public class Log {

    @Before("execution(* com.atguigu.spring.aop.impl.Cacl.*(int,int))")
    public void before(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        List<Object> args = Arrays.asList(joinPoint.getArgs());
        System.out.println("before method"+methodName+" begins with "+args);
    }
    
    //后置通知，无论是否出现异常
    @After("execution(* com.atguigu.spring.aop.impl.Cacl.*(int,int))")
    public void after(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("after method "+methodName+" ends");
    }
    
    @AfterReturning(value="execution(* com.atguigu.spring.aop.impl.Cacl.*(int,int))",returning="result")
    public void afterReturning(JoinPoint joinPoint,Object result){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("afterreturning method "+methodName+" ends with "+result);
    }
    
    @AfterThrowing(value="execution(* com.atguigu.spring.aop.impl.Cacl.*(int,int))",throwing="exception")
    public void afterThrowing(JoinPoint joinPoint,Exception exception){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("afterthrowing method "+methodName +"occurs by "+exception);
    }
    
    @Around("execution(* com.atguigu.spring.aop.impl.Cacl.*(int,int))")
    public Object around(ProceedingJoinPoint pjp){
        Object result = null;
        String methodName = pjp.getSignature().getName();
        
        try {
            System.out.println(" around method "+methodName +" begins with "+Arrays.asList(pjp.getArgs()));
            result = pjp.proceed();
            System.out.println("around method "+methodName +" ends ");
        } catch (Throwable e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return result;
    }
    
}

这些东西都不难，基本都是固定流程

③

<?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-3.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
    <!-- 配置自动扫描的包 -->
    <context:component-scan base-package="com.atguigu.spring.aop.impl"></context:component-scan>
    <!-- 使Aspectj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>

④

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");
        
        Cacl cacl = ctx.getBean(Cacl.class);
        System.out.println(cacl.add(2,3));
        System.out.println(cacl.div(10,1));
        
    }

}

⑤输出结果

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
before methodadd begins with [2, 3]
 around method add begins with [2, 3]
after method add ends
around method add ends 
afterreturning method add ends with 5
5
before methoddiv begins with [10, 1]
 around method div begins with [10, 1]
after method div ends
around method div ends 
afterreturning method div ends with 10
10