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---------------------

 
   ch.qos.logback
   logback-core
   1.1.8

-----------------log4j2--------------------


   org.springframework.boot

   spring-boot-starter-log4j2

   1.5.12.RELEASE



    org.apache.logging.log4j
    log4j
    2.7
 

-----------------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：
    
       onMismatch="DENY"/>
    

   修改后：
   
      onMismatch="NEUTRAL"/>
   

 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