Log4j输出日志到项目路径下

在web.xml中设定webAppRootKey，以避免Spring加载log4j.properties时报“Webapprootsystempropertyalreadysettodifferentvalue”错误：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<context-param>
  <param-name>webAppRootKey</param-name>
  <param-value>webAppName.root</param-value>
 </context-param>
</web-app>

再在log4j.properties设置：