与程序员相关的CPU缓存知识

预计阅读需要27分钟

写在前面

本篇文章是实战性的，对于切面的原理不会讲解，只会简单介绍一下切面的知识点

写个日志请求切面，前后端甩锅更方便

切面介绍

面向切面编程是一种编程范式，它作为OOP面向对象编程的一种补充，用于处理系统中分布于各个模块的横切关注点，比如事务管理、权限控制、缓存控制、日志打印等等。 AOP把软件的功能模块分为两个部分：核心关注点和横切关注点。业务处理的主要功能为核心关注点，而非核心、需要拓展的功能为横切关注点。AOP的作用在于分离系统中的各种关注点，将核心关注点和横切关注点进行分离，使用切面有以下好处：

  • 集中处理某一关注点/横切逻辑
  • 可以很方便的添加/删除关注点
  • 侵入性少，增强代码可读性及可维护性 因此当想打印请求日志时很容易想到切面，对控制层代码0侵入

切面的使用【基于注解】

  • @Aspect => 声明该类为一个注解类

切点注解：

  • @Pointcut => 定义一个切点，可以简化代码

通知注解：

  • @Before => 在切点之前执行代码
  • @After => 在切点之后执行代码
  • @AfterReturning => 切点返回内容后执行代码，可以对切点的返回值进行封装
  • @AfterThrowing => 切点抛出异常后执行
  • @Around => 环绕，在切点前后执行代码

动手写一个请求日志切面

  • 使用@Pointcut定义切点
@Pointcut(\"execution(* your_package.controller..*(..))\")
public void requestServer() {
}

@Pointcut定义了一个切点，因为是请求日志切边，因此切点定义的是Controller包下的所有类下的方法。定义切点以后在通知注解中直接使用requestServer方法名就可以了

  • 使用@Before再切点前执行
@Before(\"requestServer()\")
public void doBefore(JoinPoint joinPoint) {
    ServletRequestAttributes attributes = (ServletRequestAttributes) 
RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();

    LOGGER.info(\"===============================Start========================\");
    LOGGER.info(\"IP                 : {}\", request.getRemoteAddr());
    LOGGER.info(\"URL                : {}\", request.getRequestURL().toString());
    LOGGER.info(\"HTTP Method        : {}\", request.getMethod());
    LOGGER.info(\"Class Method       : {}.{}\", joinPoint.getSignature().getDeclaringTypeName(), joinPoint.getSignature().getName());
}

在进入Controller方法前，打印出调用方IP、请求URL、HTTP请求类型、调用的方法名

  • 使用@Around打印进入控制层的入参
@Around(\"requestServer()\")
public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
    long start = System.currentTimeMillis();
    Object result = proceedingJoinPoint.proceed();
    LOGGER.info(\"Request Params       : {}\", getRequestParams(proceedingJoinPoint));
    LOGGER.info(\"Result               : {}\", result);
    LOGGER.info(\"Time Cost            : {} ms\", System.currentTimeMillis() - start);

    return result;
}

通过 @PathVariable以及@RequestParam注解传递的参数无法打印出参数名，因此需要手动拼接一下参数名，同时对文件对象进行了特殊处理，只需获取文件名即可

打印了入参、结果以及耗时

  • getRquestParams方法
private Map<String, Object> getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
     Map<String, Object> requestParams = new HashMap<>();

      //参数名
     String[] paramNames = ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
     //参数值
     Object[] paramValues = proceedingJoinPoint.getArgs();

     for (int i = 0; i < paramNames.length; i++) {
         Object value = paramValues[i];

         //如果是文件对象
         if (value instanceof MultipartFile) {
             MultipartFile file = (MultipartFile) value;
             value = file.getOriginalFilename();  //获取文件名
         }

         requestParams.put(paramNames[i], value);
     }

     return requestParams;
 }

通过 @PathVariable以及@RequestParam注解传递的参数无法打印出参数名，因此需要手动拼接一下参数名，同时对文件对象进行了特殊处理，只需获取文件名即可

  • @After方法调用后执行
@After(\"requestServer()\")
public void doAfter(JoinPoint joinPoint) {
    LOGGER.info(\"===============================End========================\");
}

没有业务逻辑只是打印了End

  • 完整切面代码
@Component
@Aspect
public class RequestLogAspect {
    private final static Logger LOGGER = LoggerFactory.getLogger(RequestLogAspect.class);

    @Pointcut(\"execution(* your_package.controller..*(..))\")
    public void requestServer() {
    }

    @Before(\"requestServer()\")
    public void doBefore(JoinPoint joinPoint) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) 
RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();

        LOGGER.info(\"===============================Start========================\");
        LOGGER.info(\"IP                 : {}\", request.getRemoteAddr());
        LOGGER.info(\"URL                : {}\", request.getRequestURL().toString());
        LOGGER.info(\"HTTP Method        : {}\", request.getMethod());
        LOGGER.info(\"Class Method       : {}.{}\", joinPoint.getSignature().getDeclaringTypeName(), 
 joinPoint.getSignature().getName());
    }


    @Around(\"requestServer()\")
    public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        long start = System.currentTimeMillis();
        Object result = proceedingJoinPoint.proceed();
        LOGGER.info(\"Request Params     : {}\", getRequestParams(proceedingJoinPoint));
        LOGGER.info(\"Result               : {}\", result);
        LOGGER.info(\"Time Cost            : {} ms\", System.currentTimeMillis() - start);

        return result;
    }

    @After(\"requestServer()\")
    public void doAfter(JoinPoint joinPoint) {
        LOGGER.info(\"===============================End========================\");
    }

    /**
     * 获取入参
     * @param proceedingJoinPoint
     *
     * @return
     * */
    private Map<String, Object> getRequestParams(ProceedingJoinPoint proceedingJoinPoint) {
        Map<String, Object> requestParams = new HashMap<>();

        //参数名
        String[] paramNames = 
((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = proceedingJoinPoint.getArgs();

        for (int i = 0; i < paramNames.length; i++) {
            Object value = paramValues[i];

            //如果是文件对象
            if (value instanceof MultipartFile) {
                MultipartFile file = (MultipartFile) value;
                value = file.getOriginalFilename();  //获取文件名
            }

            requestParams.put(paramNames[i], value);
        }

        return requestParams;
    }
}

高并发下请求日志切面

写完以后对自己的代码很满意，但是想着可能还有完善的地方就和朋友交流了一下。emmmm

写个日志请求切面，前后端甩锅更方便

果然还有继续优化的地方 每个信息都打印一行，在高并发请求下确实会出现请求之间打印日志串行的问题，因为测试阶段请求数量较少没有出现串行的情况，果然生产环境才是第一发展力，能够遇到更多bug，写更健壮的代码 解决日志串行的问题只要将多行打印信息合并为一行就可以了，因此构造一个对象

  • RequestInfo.java 
@Data
public class RequestInfo {
    private String ip;
    private String url;
    private String httpMethod;
    private String classMethod;
    private Object requestParams;
    private Object result;
    private Long timeCost;
}
  • 环绕通知方法体 
@Around(\"requestServer()\")
public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
    long start = System.currentTimeMillis();
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();
    Object result = proceedingJoinPoint.proceed();
    RequestInfo requestInfo = new RequestInfo();
            requestInfo.setIp(request.getRemoteAddr());
    requestInfo.setUrl(request.getRequestURL().toString());
    requestInfo.setHttpMethod(request.getMethod());
    requestInfo.setClassMethod(String.format(\"%s.%s\", proceedingJoinPoint.getSignature().getDeclaringTypeName(),
            proceedingJoinPoint.getSignature().getName()));
    requestInfo.setRequestParams(getRequestParamsByProceedingJoinPoint(proceedingJoinPoint));
    requestInfo.setResult(result);
    requestInfo.setTimeCost(System.currentTimeMillis() - start);
    LOGGER.info(\"Request Info      : {}\", JSON.toJSONString(requestInfo));

    return result;
}

将url、http request这些信息组装成RequestInfo对象，再序列化打印对象 打印序列化对象结果而不是直接打印对象是因为序列化有更直观、更清晰，同时可以借助在线解析工具对结果进行解析

写个日志请求切面，前后端甩锅更方便

是不是还不错
在解决高并发下请求串行问题的同时添加了对异常请求信息的打印，通过使用 @AfterThrowing注解对抛出异常的方法进行处理

  • RequestErrorInfo.java
@Data
public class RequestErrorInfo {
    private String ip;
    private String url;
    private String httpMethod;
    private String classMethod;
    private Object requestParams;
    private RuntimeException exception;
}
  • 异常通知环绕体
@AfterThrowing(pointcut = \"requestServer()\", throwing = \"e\")
public void doAfterThrow(JoinPoint joinPoint, RuntimeException e) {
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();
    RequestErrorInfo requestErrorInfo = new RequestErrorInfo();
    requestErrorInfo.setIp(request.getRemoteAddr());
    requestErrorInfo.setUrl(request.getRequestURL().toString());
    requestErrorInfo.setHttpMethod(request.getMethod());
    requestErrorInfo.setClassMethod(String.format(\"%s.%s\", joinPoint.getSignature().getDeclaringTypeName(),
            joinPoint.getSignature().getName()));
    requestErrorInfo.setRequestParams(getRequestParamsByJoinPoint(joinPoint));
    requestErrorInfo.setException(e);
    LOGGER.info(\"Error Request Info      : {}\", JSON.toJSONString(requestErrorInfo));
}

对于异常，耗时是没有意义的，因此不统计耗时，而是添加了异常的打印

最后放一下完整日志请求切面代码：

@Component
@Aspect
public class RequestLogAspect {
    private final static Logger LOGGER = LoggerFactory.getLogger(RequestLogAspect.class);

    @Pointcut(\"execution(* your_package.controller..*(..))\")
    public void requestServer() {
    }

    @Around(\"requestServer()\")
    public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        long start = System.currentTimeMillis();
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        Object result = proceedingJoinPoint.proceed();
        RequestInfo requestInfo = new RequestInfo();
                requestInfo.setIp(request.getRemoteAddr());
        requestInfo.setUrl(request.getRequestURL().toString());
        requestInfo.setHttpMethod(request.getMethod());
        requestInfo.setClassMethod(String.format(\"%s.%s\", proceedingJoinPoint.getSignature().getDeclaringTypeName(),
                proceedingJoinPoint.getSignature().getName()));
        requestInfo.setRequestParams(getRequestParamsByProceedingJoinPoint(proceedingJoinPoint));
        requestInfo.setResult(result);
        requestInfo.setTimeCost(System.currentTimeMillis() - start);
        LOGGER.info(\"Request Info      : {}\", JSON.toJSONString(requestInfo));

        return result;
    }


    @AfterThrowing(pointcut = \"requestServer()\", throwing = \"e\")
    public void doAfterThrow(JoinPoint joinPoint, RuntimeException e) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        RequestErrorInfo requestErrorInfo = new RequestErrorInfo();
        requestErrorInfo.setIp(request.getRemoteAddr());
        requestErrorInfo.setUrl(request.getRequestURL().toString());
        requestErrorInfo.setHttpMethod(request.getMethod());
        requestErrorInfo.setClassMethod(String.format(\"%s.%s\", joinPoint.getSignature().getDeclaringTypeName(),
                joinPoint.getSignature().getName()));
        requestErrorInfo.setRequestParams(getRequestParamsByJoinPoint(joinPoint));
        requestErrorInfo.setException(e);
        LOGGER.info(\"Error Request Info      : {}\", JSON.toJSONString(requestErrorInfo));
    }

    /**
     * 获取入参
     * @param proceedingJoinPoint
     *
     * @return
     * */
    private Map<String, Object> getRequestParamsByProceedingJoinPoint(ProceedingJoinPoint proceedingJoinPoint) {
        //参数名
        String[] paramNames = ((MethodSignature)proceedingJoinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = proceedingJoinPoint.getArgs();

        return buildRequestParam(paramNames, paramValues);
    }

    private Map<String, Object> getRequestParamsByJoinPoint(JoinPoint joinPoint) {
        //参数名
        String[] paramNames = ((MethodSignature)joinPoint.getSignature()).getParameterNames();
        //参数值
        Object[] paramValues = joinPoint.getArgs();

        return buildRequestParam(paramNames, paramValues);
    }

    private Map<String, Object> buildRequestParam(String[] paramNames, Object[] paramValues) {
        Map<String, Object> requestParams = new HashMap<>();
        for (int i = 0; i < paramNames.length; i++) {
            Object value = paramValues[i];

            //如果是文件对象
            if (value instanceof MultipartFile) {
                MultipartFile file = (MultipartFile) value;
                value = file.getOriginalFilename();  //获取文件名
            }

            requestParams.put(paramNames[i], value);
        }

        return requestParams;
    }

    @Data
    public class RequestInfo {
        private String ip;
        private String url;
        private String httpMethod;
        private String classMethod;
        private Object requestParams;
        private Object result;
        private Long timeCost;
    }

    @Data
    public class RequestErrorInfo {
        private String ip;
        private String url;
        private String httpMethod;
        private String classMethod;
        private Object requestParams;
        private RuntimeException exception;
    }
}

赶紧给你们的应用加上吧【如果没加的话】，没有日志的话，总怀疑上层出错，但是却拿不出证据

作者：何甜甜在吗
原文链接：https://juejin.im/post/5e69d5b5e51d45183840b351

本文系本站编辑转载，文章版权归原作者所有，内容为作者个人观点，转载目的在于传递更多信息，并不代表本站赞同其观点和对其真实性负责。如涉及作品内容、版权和其它问题，请与本站联系，本站将在第一时间删除内容！
上一篇

「价值精选」动力电池王者，深度受益新能源汽车大潮

下一篇

她本没想嫁入豪门，被富家公子追了10年，有情人终成眷属！

评论已经被关闭。

插入图片
返回顶部