IDEA报错：log4j:WARN No appenders could be found for logger (org.mybatis.generator.internal.db.Databas）

报错信息：

log4j:WARN No appenders could be found for logger (org.mybatis.generator.internal.db.DatabaseIntrospector).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

缘由：

解决方法：