log4j2和logback动态修改日志级别工具类

工作中，在排查线上问题时，有以下场景在不重新部署或重启服务的情况下，需要动态调整线上日志级别

1、线上有些日志打印过多干扰有用的日志，需要动态修改线上日志记录器的打印日志级别，调高一些日志级别，打印出更少的干扰日志

2、由于线上日志级别打印的相关有用日志太少，需要动态修改线上日志记录器的打印日志级别，调低一些日志级别，打印出更多的有用日志

本文的两个工具类使用的版本如下：

----------------logback---------------------

<dependency>
   <groupId>ch.qos.logback</groupId>
   <artifactId>logback-core</artifactId>
   <version>1.1.8</version>
</dependency>
-----------------log4j2--------------------
<dependency>

   <groupId>org.springframework.boot</groupId>

   <artifactId>spring-boot-starter-log4j2</artifactId>

   <version>1.5.12.RELEASE</version>

</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>2.7</version>
 </dependency>

-----------------Log4j2Controller-------------------------

@Api(tags = "Log4j2Controller",description = "Log4j2控制类")
@RestController
@RequestMapping("/log/control")
public class Log4j2Controller {
    private static final Logger logger = LoggerFactory.getLogger(Log4j2Controller.class);

    @RequestMapping(value = "/getLoglevel", method = {RequestMethod.GET, RequestMethod.POST}, produces = "application/json;charset=UTF-8")
    public Level getLoglevel(@RequestParam(value="package") String packageName) throws Exception {//package 指定修改日志级别的包路径 ，如 org.mybatis
           logger.info("getLoglevel packageName is {}",packageName);
           LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
          return  ctx.getLogger(packageName).getLevel();
    }

    @RequestMapping(value = "/setLoglevel", method = {RequestMethod.GET, RequestMethod.POST}, produces = "application/json;charset=UTF-8")
    public String setLoglevel(@RequestParam("loglevel") String logLevel, @RequestParam(value="package") String packageName) throws Exception {

        logger.info("setLoglevel packageName is {},logLevel is {}",packageName,logLevel);
        try{
        Configurator.setLevel(packageName,Level.valueOf(logLevel));
        }catch (Exception e){
            logger.error("Exception setLoglevel packageName is {},logLevel is {}",packageName,logLevel,e);
            return "fail";
        }
        return "success";
    }
    @RequestMapping(value = "/setRootLoglevel", method = {RequestMethod.GET, RequestMethod.POST}, produces = "application/json;charset=UTF-8")
    public String setRootLoglevel(@RequestParam("loglevel") String logLevel) throws Exception {
        logger.info("setRootLoglevel ,logLevel is {}",logLevel);
        try {
            //设置根记录器
            Configurator.setRootLevel(Level.valueOf(logLevel));
        }catch (Exception e){
            logger.error("Exception setRootLoglevel ,logLevel is {}",logLevel,e);
            return  "fail";
        }
        return "success";
    }
    @RequestMapping(value = "/testLoglevel", method = {RequestMethod.GET, RequestMethod.POST}, produces = "application/json;charset=UTF-8")
    public String testLoglevel() throws Exception {
        logger.debug("current log level is debug..........debug...");
        logger.info("current log level is info.........info......");
        logger.warn("current log level is warn.......warn.......");
        logger.error("current log level is error.......error.......");

        return "success";
    }
}

-----------------LogbackController-------------------------

@Api(tags = "LogbackController",description = "logback控制类")
@RestController
@RequestMapping("/log/control")
public class LogbackController {
    private static Logger logger = LoggerFactory.getLogger(LogbackController.class);

    @RequestMapping(value = "/getLoglevel", method = {RequestMethod.GET, RequestMethod.POST}, produces = "application/json;charset=UTF-8")
    public Level getLoglevel(@RequestParam(value="package") String packageName) throws Exception {//package 指定修改日志级别的包路径 ，如 org.mybatis
        logger.info("getLoglevel packageName is {}",packageName);
        LoggerContext loggerContext = (LoggerContext)LoggerFactory.getILoggerFactory();
        return loggerContext.getLogger(packageName).getLevel();
    }

    @RequestMapping(value = "/setLoglevel", method = {RequestMethod.GET, RequestMethod.POST})
    @ResponseBody
    public String setLoglevel(@RequestParam("loglevel") String logLevel, @RequestParam(value="package") String packageName) throws Exception {
        logger.info("setLoglevel packageName is {},logLevel is {}",packageName,logLevel);
        try{
        LoggerContext loggerContext =(LoggerContext)LoggerFactory.getILoggerFactory();
        loggerContext.getLogger(packageName).setLevel(Level.valueOf(logLevel));
        }catch (Exception e){
            logger.error("Exception packageName is {},logLevel is {}",packageName,logLevel,e);
            return "fail";
        }
        return "success";
    }

    @RequestMapping(value = "/setRootLoglevel", method = {RequestMethod.GET, RequestMethod.POST})
    @ResponseBody
    public String setRootLoglevel(@RequestParam("loglevel") String logLevel) throws Exception {
        logger.info("setRootLoglevel ,logLevel is {}",logLevel);
        try{
            LoggerContext loggerContext =(LoggerContext)LoggerFactory.getILoggerFactory();
            //设置全局日志级别
            ch.qos.logback.classic.Logger logger=loggerContext.getLogger("root");
            logger.setLevel(Level.toLevel(logLevel));
        }catch (Exception e){
            logger.error("Exception setRootLoglevel,logLevel is {}",logLevel,e);
            return "fail";
        }
        return "success";
    }

    @RequestMapping(value = "/testLoglevel", method = {RequestMethod.GET, RequestMethod.POST})
    @ResponseBody
    public String testLoglevel() throws Exception {
        logger.debug("current log level is debug..........debug...");
        logger.info("current log level is info.........info......");
        logger.warn("current log level is warn.......warn.......");
        logger.error("current log level is error.......error.......");

        return "success";
    }
}

备注：
1、logback和log4j2也有其它方式动态修改日志，但需要有方案或权限修改线上部署服务器的修改权限
      比如logback.xml中的configuration标签有<configuration scan="true" scanPeriod="60 seconds" debug="false">这种配置，
  其中的scan如果设置为true的话，项目在启动后就会默认每一分钟自动扫描配置文件，如果有改变则重新加载，而我们还可以设置自动扫描的时间间隔属性scanPeriod，可以设置成30秒或者5分钟。
  现在只要在logback.xml中添加一个属性，以后可以直接在服务器上修改logback.xml中root的level属性或者直接替换整个logback.xml文件，然后过会项目的日志输出级别就会改变了，不需要再重启项目。 
  2、本文主要介绍代码动态修改线上日志级别
  3、log4j2遇到的坑，如果把某个logger的日志级别修改成debug，日志文件一直不会打印，但控制台会正常打印。
   经排查是log4j2.xml中appender的过滤级别配置导致的，如下：
   修改前：
    <Filters>
       <ThresholdFilter level="info" onMatch="ACCEPT"  onMismatch="DENY"/>
    </Filters>

   修改后：
   <Filters>
      <ThresholdFilter level="info" onMatch="ACCEPT"  onMismatch="NEUTRAL"/>
   </Filters>

 简单对比说明：
  onMatch和onMismatch都有三个属性值：Accept、DENY和NEUTRAL
  onMatch="ACCEPT" 表示匹配该级别及以上
  onMatch="DENY"   表示不匹配该级别及以上
  onMatch="NEUTRAL" 表示该级别及以上的，由下一个filter处理，如果当前是最后一个，则表示匹配该级别及以上
  onMismatch="ACCEPT" 表示匹配该级别以下
  onMismatch="NEUTRAL" 表示该级别及以下的，由下一个filter处理，如果当前是最后一个，则不匹配该级别以下的
  onMismatch="DENY" 表示不匹配该级别以下的