编辑：用于log4j2的最新版本，请参阅 https://***.com/a/ 33472893/1899566 反而。

for the newest versions of log4j2, see https://***.com/a/33472893/1899566 instead.

我得到的印象是他们不希望你这样做，但这对我有用：

I get the impression they don't want you doing this, but this works for me:

if (arg[0].equals("log") ) {
  org.apache.logging.log4j.Logger logger
    = org.apache.logging.log4j.LogManager.getLogger("loggerNameFromXMLConfig");
  org.apache.logging.log4j.core.Logger coreLogger
    = (org.apache.logging.log4j.core.Logger)logger;
  org.apache.logging.log4j.core.LoggerContext context
    = (org.apache.logging.log4j.core.LoggerContext)coreLogger.getContext();
  org.apache.logging.log4j.core.config.BaseConfiguration configuration
    = (org.apache.logging.log4j.core.config.BaseConfiguration)context.getConfiguration();

  coreLogger.addAppender(configuration.getAppender("appenderNameFromXMLConfig"));
} else {
  //...
}