有关log4j日志文件输出为相对路径的二种方法，将日志文件输出到tomcat自身的日志文件夹logs中、将日志文件输出到自己程序WEB-INF\logs目录中，需要的朋友参考下。
方法1，将日志文件输出到tomcat自身的日志文件夹logs中
复制代码 代码示例:
# Set root category priority to info and its only appender to console.
log4j.rootCategory=info,console,R
#log4j.debug=true
# console is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.console=org.
apache.log4j.ConsoleAppender
log4j.appender.console.Threshold=info
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=- %m%n
# R is set to be a File appender using a PatternLayout.
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.Append=true
log4j.appender.R.Threshold=info
log4j.appender.R.MaxFileSize=1024KB
log4j.appender.R.MaxBackupIndex=10
log4j.appender.R.File=../logs/abc.log
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
方法2，将日志文件输出到自己程序WEB-INFlogs目录中
1、在web.xml配置一个servlet文件
复制代码 代码示例:
<servlet>
<servlet-name>lo4jInit</servlet-name>
<servlet-class>com.linder.util.log4j.init.Lo4jInit</servlet-class>
<init-param>
<param-name>log4j_init_path</param-name>
<param-value>WEB-INFclasseslog4j.properties</param-value>
</init-param>
<init-param>
<param-name>log4j_file_path</param-name>
<param-value>WEB-INFlogs</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>
2、编写一个初始化log4j的Servlet
复制代码 代码示例:
package com.linder.util.log4j.init;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
public class Lo4jInitextends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private static Logger logger=Logger.getLogger(Lo4jInit.class);
public void init(){
String path=this.getServletContext().getRealPath("/");
String file=this.getInitParameter("log4j_init_path");
String logFile=this.getInitParameter("log4j_file_path");
if(file!=null)
{
Properties prop = new Properties();
try{
prop.load(new FileInputStream(path+file)); //加载log4j.properties
prop.setProperty("log4j.appender.R.File", path+logFile+ prop.getProperty("log4j.appender.R.File")); //设置日志文件的输出路径
PropertyConfigurator.configure(prop); //加载配置项
}catch(Exception e)
{
logger.info("初始化log4j日志输入路径异常，请检查web.xml参数配置是否正常，异常发生在"+this.getClass().getName()+"类的public void init()方法，异常的愿意是："+e.getMessage(), e.fillInStackTrace());
}
}
}
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
}
3、log4j.properties配置信息
复制代码 代码示例:
# Set root category priority to info and its only appender to console.
log4j.rootCategory=info,console,R
#log4j.debug=true
# console is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.Threshold=info
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=- %m%n
# R is set to be a File appender using a PatternLayout.
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.Append=true
log4j.appender.R.Threshold=info
log4j.appender.R.MaxFileSize=1024KB
log4j.appender.R.MaxBackupIndex=10
log4j.appender.R.File=abc.log
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n
