用eclipse运行web项目时遇到的错误ERROR Could not find value for key log4j.appender.file

[花落月西]

错误如下：
2017-08-25 10:07:14.798:INFO:oejs.Server:main: jetty-9.2.11.v20150529
log4j:ERROR Could not find value for key log4j.appender.file
log4j:ERROR Could not instantiate appender named "file".
log4j:ERROR Could not find value for key log4j.appender.file
log4j:ERROR Could not instantiate appender named "file".
log4j:ERROR Could not find value for key log4j.appender.file
log4j:ERROR Could not instantiate appender named "file".
log4j:ERROR Could not find value for key log4j.appender.file
log4j:ERROR Could not instantiate appender named "file".
有大神知道是怎么回事么？得怎么解决呀。