一：搭建好Selenium+testNG+Maven环境，可参考
http://www.cnblogs.com/hc1020/p/8602863.html
二：百度搜索Maven仓库，然后搜索Log4j.jar，点击需要的版本，Copy如下的信息至Pom.xml中（本博主选的是1.2.17版本）
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.</version>
</dependency>
三：在src这个根目录下创建Log4j.properties文件，然后搜索Log4j配置Copy到Log4j.properties中。Log4j配置如下：
### \u8BBE\u7F6E###
log4j.rootLogger = debug,stdout,D,E ### \u8F93\u51FA\u4FE1\u606F\u5230\u63A7\u5236\u62AC ###
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 = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n ### \u8F93\u51FADEBUG \u7EA7\u522B\u4EE5\u4E0A\u7684\u65E5\u5FD7\u5230=E://logs/error.log ###
log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = logs/log.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n ### \u8F93\u51FAERROR \u7EA7\u522B\u4EE5\u4E0A\u7684\u65E5\u5FD7\u5230=E://logs/error.log ###
log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File = logs/error.log
log4j.appender.E.Append = true
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} [ %t:%r ] - [ %p ] %m%n
四：在需要调用的类中，引用
Logger logger=Logger.getLogger(类名.class);
然后调用即可
logger.info("This is Log4j information");