spring Aop切面中的@Before @Around等执行顺序与请求参数统一解码

1.背景

　　在实际开发中,我可能会对请求接口做统一日志输出,或者统一参数解析,验签,统一响应加密等,通常会用到aop,实际案例如下

2.代码

package com.qianxingniwo.log;

import com.alibaba.fastjson.JSON;

import com.qianxingniwo.exception.ParamException;

import org.aspectj.lang.JoinPoint;

import org.aspectj.lang.ProceedingJoinPoint;

import org.aspectj.lang.annotation.*;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.stereotype.Component;

import org.springframework.web.context.request.RequestContextHolder;

import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;

/**

 * @Copyright (C)

 * @Author:

 * @Date: 2019/4/8 10:11

 * @Description: <p>

 * aop的几个重要概念

 * 切面(做什么事情,切入后要执行的业务)

 * 切入点(在什么地点,具体到方法,一般使用通配符 或 注解)

 * 切入时机(在什么时候,方法执行前,方法执行后,抛异常的时候)

 * </p>

 */

@Aspect//定义切面

@Component //加入spring容器

@SuppressWarnings("all")//注解主要用在取消一些编译器产生的警告

public class SystemLogAspect {

    /**

     * 本地异常日志记录对象

     */

    private static final Logger log = LoggerFactory.getLogger(SystemLogAspect.class);

    /**

     * Controller层切点

     */

    @Pointcut("execution(* com.qianxingniwo.*.controller.*Controller.*(..))")

    public void controllerAspect() {

    }

    /**

     * 可以修改请求参数,如实际生成中,将请求参数解密等

     *

     * @param joinPoint

     * @return

     * @throws Throwable

     */

    @Around("controllerAspect()")

    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {

        System.out.println("@Around=1=方法执行前" + System.currentTimeMillis());

        Object[] obj = joinPoint.getArgs();

        System.out.println("@Around=2=请求参数" + JSON.toJSONString(obj));

        //  Object obj2 = joinPoint.proceed();

        // System.out.println("@Around=3=方法后" + System.currentTimeMillis() + "--" + obj2);

        //  System.out.println("@Around：被织入的目标对象为：" + joinPoint.getTarget());

        //  System.out.println("@Around：原返回值：" + JSON.toJSONString(obj2) + "，这是返回结果的后缀");

        // JSONObject jsonObject = JSON.parseObject(JSON.toJSONString(obj[0]));

        //通过反射实例化参数对象

        //获取字节码

        Class<?> aClass = obj[0].getClass();

        //实例化对象

        Object instance = aClass.newInstance();

        //获取执行方法 获取父类方法 setDataList

        //Method method = aClass.getDeclaredMethod("put", Object.class);

        Method method = aClass.getSuperclass().getMethod("put", Object.class);

        List<Integer> dataList = new ArrayList<>();

        dataList.add(1);

        dataList.add(2);

        //执行方法

        method.invoke(instance, dataList);

        // jsonObject.put("dataList", dataList);

        obj[0] = instance;

        //obj[0] = MAPPER.writeValueAsString("");

        System.out.println("=====修改参数==========");

        return joinPoint.proceed(obj);

    }

    /**

     * 切入时机

     *

     * @param joinPoint

     * @Description 前置通知  用于拦截Controller层记录用户的操作

     */

    @Before("controllerAspect()")

    public void doBefore(JoinPoint joinPoint) throws ParamException {

        System.out.println("@Before==" + System.currentTimeMillis());

        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

        Thread.currentThread().setName(UUID.randomUUID().toString().substring(0, 12));

        String params = "";

        if (joinPoint.getArgs() != null && joinPoint.getArgs().length > 0) {

            String data = JSON.toJSONString(joinPoint.getArgs()[0]);

            params += data;

        }

        //获取用户请求方法的参数并序列化为JSON格式字符串

        //打印请求内容

        String url = request.getRequestURL().toString();

        log.info("===============请求内容===============");

        log.info("请求地址:" + url);

        log.info("请求方式:" + request.getMethod());

        log.info("请求类方法:" + joinPoint.getSignature());

        log.info("请求类方法参数:" + params);

        log.info("===============请求内容===============");

    }

    @After("controllerAspect()")

    public void After(JoinPoint point) {

        System.out.println("@After==" + System.currentTimeMillis());

       /* System.out.println("@After：模拟释放资源...");

        System.out.println("@After：目标方法为：" +

                point.getSignature().getDeclaringTypeName() +

                "." + point.getSignature().getName());

        System.out.println("@After：参数为：" + Arrays.toString(point.getArgs()));

        System.out.println("@After：被织入的目标对象为：" + point.getTarget());*/

    }

    /**

     * 统一修改响应结果,如加密等

     *

     * @param joinPoint

     * @param o

     * @throws Exception

     */

    @AfterReturning(returning = "o", pointcut = "controllerAspect()")

    public void methodAfterReturing(JoinPoint joinPoint, Object o) throws Exception {

        System.out.println("@AfterReturning==" + System.currentTimeMillis());

        System.out.println("@AfterReturning：模拟日志记录功能...");

        log.info("--------------返回内容----------------");

        log.info("Response内容:" + JSON.toJSONString(o));

        log.info("--------------返回内容----------------");

       /* ResponseMessage responseMessage = (ResponseMessage) o;

        byte[] a = Base64Utils.encode(JSON.toJSONString(o).getBytes());

        responseMessage.setMsg(new String(a ));

        log.info("请求返回值【{}】", object.toString());*/

    }

    @AfterThrowing("controllerAspect()")

    public void AfterThrowing() {

        System.out.println("@AfterThrowing==" + System.currentTimeMillis());

        System.out.println("异常通知....");

    }

}

　　执行结果如下:

　　

3.执行流程图解

　　

　　完美!