log4j日志文件路径问题

做了一个最简单的servlet项目，只有一个servlet，然后想在servlet把日志记录到项目下的logs文件夹中的logRecord.log和logRecorderror.log。

然而路径问题弄了我一天，找了很多资料，绝对路径是可以解决，但是如果移植的话，那么绝对路径改起来会很麻烦。所以最好用相对路径。

但是网上的相关资料都无法解决我的问题，后来一不做二不休，瞎弄，发现路径直接写logs/logRecord.log竟然成功的把日志写入进去了。

好了，话不多说直接上代码。

1.首先我们把

commons-logging-1.1.3.jar
log4j-1.2.17.jar

导入到项目中。

2.配置log4j.properties

### set log levels ###
log4j.rootLogger = INFO, stdout, D, E
#log4j.rootLogger = INFO, stdout
#log.path = /mylog

###ãè¾åºå°æ§å¶å° ###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern =  %d{yyyy/MM/dd-HH:mm:ss} [%-5p] [%c] [%F] - %m %n

### è¾åºå°æ¥å¿æä»¶ ###
log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = logs/logRecord.log
log4j.appender.D.DatePattern='.'yyyy-MM-dd
log4j.appender.D.Threshold = INFO
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %d{yyyy/MM/dd-HH:mm:ss} [%-5p] [%c] [%F] - %m %n
log4j.appender.D.layout.Encoding=UTF-8

### ä¿åå¼å¸¸ä¿¡æ¯å°åç¬æä»¶ ###
log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
##å¼å¸¸æ¥å¿æä»¶
log4j.appender.E.File = logs/logRecorderror.log
log4j.appender.E.Append = true
##åªè¾åºERRORçº§å«ä»¥ä¸çæ¥å¿
log4j.appender.E.Threshold = ERROR 
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern = %d{yyyy/MM/dd-HH:mm:ss} [%-5p] [%c] [%F] - %m %n
log4j.appender.E.DatePattern='.'yyyy-MM-dd
log4j.appender.E.Encoding=UTF-8

这个是servlet，里面的main方法是来把日志写入文件中。

package com.pingpay.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class PingPayLogServlet extends HttpServlet {

// 在任何需要记录日志的类中

Log log = LogFactory.getLog(this.getClass());

/**
 * 记录ping++返回的数据
 * 
 */
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

//response.setContentType("text/html");
//request.setCharacterEncoding("utf-8");
//response.setCharacterEncoding("utf-8");

log.info("into one method");

try {

System.out.println(9 / 0);

} catch (RuntimeException e) {

log.error(e.getMessage());

}

log.info("out one method");

}

public static void main(String[] args) throws Exception {
new PingPayLogServlet().doPost(null, null);
System.out.println("1");
}

}

log4j日志文件路径问题

项目结构如图。

因为我们在log4j.properties中设置了log4j.appender.D.Threshold = INFO，log4j.appender.E.Threshold = ERROR 。

所以error的日志会保存在logRecorderror.log文件中，

但是由于：DEBUG < INFO < WARN < ERROR < FATAL级别

log4j.appender.D.Threshold = INFO这句话
它的作用是输出INFO级别以上的内容到logRecord.log中，所以logRecord.log文件中包含了ERROR级别的文件。

如有错误，请指出，谢谢。

周一回来发现上面的方法不行了。我也是醉了，然后换了一种方法。

将日志文件输出到自己程序WEB-INF\logs目录中

1、在web.xml配置一个servlet

<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-INF\classes\log4j.properties</param-value>
 </init-param>
 <init-param>
 <param-name>log4j_file_path</param-name>
 <param-value>WEB-INF\logs\</param-value>
 </init-param>
 <load-on-startup>0</load-on-startup>
 </servlet>

2、编写一个初始化log4j的Servlet

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 Lo4jInit   extends 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的配置信息

# 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

abc.log位于你项目的WEB-INF/logs的文件夹下。

我项目的XML配置为：

<?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">

<servlet>
<servlet-name>lo4jInit</servlet-name>
<servlet-class>com.pingpay.servlet.Lo4jInit</servlet-class>
<init-param>
<param-name>log4j_init_path</param-name>
<param-value>WEB-INF\classes\log4j.properties</param-value>
</init-param>
<init-param>
<param-name>log4j_file_path</param-name>
<param-value>WEB-INF\logs\</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>

<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>PingPayServlet</servlet-name>
<servlet-class>com.pingpay.servlet.PingPayServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>PingPayServlet</servlet-name>
<url-pattern>/PingPayServlet</url-pattern>
</servlet-mapping>


</web-app>

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log4j日志文件路径问题

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