在使用log4j進行日誌檔案輸出時，並不能夠預設輸出到專案根目錄，或者輸出到相對路徑，只能輸出到絕對路徑。

經修改配置檔案得到有效解決：

1.配置監聽器

通過監聽器獲取專案絕對路徑，並且配置系統屬性變數

package com.wd.listener;
 
import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
 
import javax.servlet.annotation.WebListener;
@WebListener
public class applicationListener implements ServletContextListener,ServletContextAttributeListener{
 
    
    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        System.getProperties().remove("log4jDirKey");
    }
 
    @Override
    
 
public void contextInitialized(ServletContextEvent arg0) {
        String log4jDir=arg0.getServletContext().getRealPath("/");
        System.setProperty("log4jDirKey", log4jDir);
    }
 
}

2.配置lolog4j.properties

使用${log4jDirKey}獲取專案根目錄，並且配置到log4j.properties中

 
log4j.rootCategory=ERROR, CONSOLE,LOGFILE
log4j.logger.com.wd.mapper.PeopleMapper
 
=DEBUG
 
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=-%p-%d{yyyy/MM/dd HH:mm:ss,SSS}-%l-%L-%m%n
 
 
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=${log4jDirKey}/myLogs.log
log4j.appender.LOGFILE.Append=false
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=-%p-%d{yyyy/MM/dd HH:mm:ss,SSS}-%l-%L-%m%n