log4j配置（总结）上

学习log4j刚开始从网上找一些例子，相当粗糙也不给力，花了两天功夫现在明白点，总算是搞定了。

做个笔记。很给力的写下自己的心得。

1.log4j 硬编码在程序里.

下面给几个例子：

在这之前你得干两件事:

首先你得下载log4j.jar,找不到就迅雷下载,百度也可以搜到,解压后,会找到一个log4j-1.2.16.jar 如图：

最后，将log4j-1.2.1.16.jar 引进来,担心说的不明白,见图:

没有lib就新建一个文件夹,将jar复制进去,然后点击右键--->build path-->add jar

那么下面的代码才不会提示错误.

 

基本示例

 

a.这里是一个非常简单的例子，程序实现了SimpleLayout和FileAppender:

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.SimpleLayout;

import org.apache.log4j.FileAppender;

public class simpandfile {

static Logger logger = Logger.getLogger(simpandfile.class); //日志记录器

public static void main(String args[]) {

SimpleLayout layout = new SimpleLayout(); //输出格式：级别-日志信息

      FileAppender appender = null;

      try {

        appender = new FileAppender(layout,"output1.txt",false); //对指定的文件不进行追加的方式输出

        logger.addAppender(appender);

        logger.setLevel((Level) Level.DEBUG);

        logger.debug("11Here is some DEBUG");

        logger.info("Here is some INFO");

        logger.warn("Here is some WARN");

        logger.error("Here is some ERROR");

        logger.fatal("Here is some FATAL");

      } catch(Exception e) {}

}

 

 

b.这里是一个非常简单的例子，程序实现了 HTMLLayout和WriterAppender:

import java.io.*;

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.HTMLLayout;

import org.apache.log4j.WriterAppender;

public class htmlandwrite {

static Logger logger = Logger.getLogger(htmlandwrite.class);

public static void main(String args[]) {

HTMLLayout layout = new HTMLLayout();

      WriterAppender appender = null;

      try {

        FileOutputStream output = new FileOutputStream("output2.html");

        appender = new WriterAppender(layout,output);

        logger.addAppender(appender);

        logger.setLevel((Level) Level.DEBUG);

        logger.debug("Here is some DEBUG");

        logger.info("Here is some INFO");

        logger.warn("Here is some WARN");

        logger.error("Here is some ERROR");

        logger.fatal("Here is some FATAL");

      } catch(Exception e) {}

}

 

 

c.这里是一个非常简单的例子，程序实现了PatternLayout和ConsoleAppender:

import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.apache.log4j.PatternLayout;

import org.apache.log4j.ConsoleAppender;

public class consandpatt {

static Logger logger = Logger.getLogger(consandpatt.class);

public static void main(String args[]) {

// Note, %n is newline

      String pattern =  "Milliseconds since program start: %r %n";

      pattern += "Classname of caller: %C %n";

      pattern += "Date in ISO8601 format: %d{ISO8601} %n";

      pattern += "Location of log event: %l %n";

      pattern += "Message: %m %n %n";

      PatternLayout layout = new PatternLayout(pattern);

      ConsoleAppender appender = new ConsoleAppender(layout);

      logger.addAppender(appender);

      logger.setLevel((Level) Level.DEBUG);

      logger.debug("Here is some DEBUG");

      logger.info("Here is some INFO");

      logger.warn("Here is some WARN");

      logger.error("Here is some ERROR");

      logger.fatal("Here is some FATAL");

   }

}

 

通过运行,查看运行结果

+上面标题为：

log4j Logger and FileAppender 的学习
log4j HTMLLayout和WriterAppender学习

 

结合看是没有大问题问题的。

 

下面接着 log4j的外部配置