【Spring】16 AOP 切面的优先级

使用 @Order 注解指定切面的优先级，值越小优先级越高

VlidationAspect.java(com.test.spring.aop.VlidationAspect)

package com.test.spring.aop;

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;
import java.util.Arrays;

@Order(1)
@Aspect
@Component
public class VlidationAspect {

    @Before("execution(public int com.test.spring.aop.ArithmeticCalculator.*(..))")
    public void validateArgs(JoinPoint joinPoint){
        System.out.println("--> validate：" + Arrays.asList(joinPoint.getArgs()));
    }
}

LoggingAspect.java(com.test.spring.aop.LoggingAspect)

package com.test.spring.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import java.util.Arrays;

/**
 * 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 {

    /**
     *  在 com.test.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("execution(public int com.test.spring.aop.ArithmeticCalculator.*(..))")
    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
     * @param joinPoint
     */
    @After("execution(public int com.test.spring.aop.ArithmeticCalculator.*(..))")
    public void afterMethod(JoinPoint joinPoint){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " ends");
    }

    /**
     * 在方法正常结束后执行的代码
     * 返回通知是可以访问到方法的返回值的！
     */
    @AfterReturning(value="execution(public int com.test.spring.aop.ArithmeticCalculator.*(..))",
        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="execution(public int com.test.spring.aop.ArithmeticCalculator.*(..))",
        throwing = "ex")
    public void afterThrowing(JoinPoint joinPoint, Exception ex){
        String methodName = joinPoint.getSignature().getName();
        System.out.println("The method " + methodName + " occurs exception " + ex);
    }
}

其他文件

ArithmeticCalculator.java(com.test.spring.aop.ArithmeticCalculato)

package com.test.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);

}

ArithmeticCalculatorImpl.java(com.test.spring.aop.ArithmeticCalculatorImpl)

package com.test.spring.aop;

import org.springframework.stereotype.Component;

@Component("arithmeticCalculator")
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;
    }
}

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: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">

    <!-- 配置自动扫描的包 -->
    <context:component-scan base-package="com.test.spring.aop"></context:component-scan>

    <!-- 配置自动为匹配 sapectJ 注解的 Java 类生成代理对象 -->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>

</beans>

Main.java(com.test.spring.aop.Main)

package com.test.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);
    }
}