code: public static void reconfigure(InputStream config, LoggerContext context) {
          if (context == null) {
              throw new NullPointerException("LoggerContext must not be null");
          }
          LoggerContext lc = context;
          JoranConfigurator jc = new JoranConfigurator();
          jc.setContext(lc);
          StatusUtil statusUtil = new StatusUtil(lc);
          List<SaxEvent> eventList = jc.recallSafeConfiguration();
  
          URL mainURL = ConfigurationWatchListUtil.getMainWatchURL(lc);
          lc.reset();
          long threshold = System.currentTimeMillis();
          try {
              jc.doConfigure(config);
              if (statusUtil.hasXMLParsingErrors(threshold)) {
                  fallbackConfiguration(lc, eventList, mainURL);
              }
          } catch (JoranException e) {
              fallbackConfiguration(lc, eventList, mainURL);
          }
      }
docs: 重新配置当前logback
  
  @param config logback的xml配置文件
  @param context 要配置的context