1、把log4j2相關(guān)的jar包導(dǎo)入到WEB-INF的lib目錄下
log4j-api-2.6.2.jar
log4j-core-2.6.2.jar
2、在src目錄下添加log4j2的配置文件
（1）log4j2.xml配置文件，以下是一個(gè)把日志輸出到控制臺(tái)和保存在文件中的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" name="MyApp">
    <appenders>
        <Console name="Console" target="SYSTEM_OUT">    
            <ThresholdFilter level="debug"/>    
            <PatternLayout pattern="%m%n"/>    
        </Console>    
        <File name="log" fileName="e:\\test1.log" append="true">
            <ThresholdFilter level="error"/>
            <PatternLayout pattern="%d-%m%n"/>    
        </File>  
    </appenders>

    <loggers>
        <root level="debug">
            <appender-ref ref="Console"></appender-ref>
            <appender-ref ref="log"></appender-ref>
        </root>
    </loggers>
</Configuration>

如果需要復(fù)雜一些的請(qǐng)參考：http://www.cnblogs.com/hanfight/p/5721855.html

（2）log4j2.properties配置文件，功能同上

status = warn
name = MyApp

filter.threshold.type = ThresholdFilter
filter.threshold.level = debug

appender.console.type = Console
appender.console.name = STDOUT
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %m%n

appender.rolling.type = File
appender.rolling.name = log
appender.rolling.append = true
appender.rolling.fileName = e:\\test1.log
appender.rolling.layout.type = PatternLayout
appender.rolling.layout.pattern = %d-%m%n

rootLogger.level = debug
rootLogger.appenderRef.stdout.ref = STDOUT
rootLogger.appenderRef.log.ref = log

如果需要復(fù)雜的請(qǐng)參考：
http://logging./log4j/2.x/manual/configuration.html#Properties

注：.properties這種方式用的比較少，鏈接中的注釋也比較少，請(qǐng)參考（1）中的文檔，對(duì)照著理解和編寫(xiě)。

3、輸出log日志并記錄成文件

//1.定義Logger對(duì)象，用Logger.getLogger(Class clazz):
public static Logger log4jDemo1 = LogManager.getLogger(LogListener.class.getName());

//2.定義Logger對(duì)象，用LogManager.getLogger(Class clazz):
//public static Logger log4jDemo2 = LogManager.getLogger(LogListener.class);

//3.定義Logger對(duì)象，用LogManager.getLogger(String name):
//public static Logger log4jDemo3 = LogManager.getLogger(LogListener.class.getName());

//4.定義Logger對(duì)象，將3中的name變成具體的字符串:
//public static Logger log4jDemo4 = LogManager.getLogger("common.LogListener");

log4jDemo1.debug("我是debug");
log4jDemo1.error("我是error");
log4jDemo1.log(Level.ERROR, "我是Level.ERROR ");
文件名log4j2.properties
private static Logger log=(Logger) LogManager.getLogger(Loger4jlisentr.class.getName());

 public void attributeAdded(ServletContextAttributeEvent arg0)  { 

    	log.debug("添加了一個(gè)application屬性!屬性名稱(chēng)為="+arg0.getName()+"值為: "+arg0.getValue());
    	log.error("沒(méi)有報(bào)錯(cuò)，這是測(cè)試！1234567890");
    }