log4j加载配置

1.web项目中log4j配置
（1）web.xml配置

<!--如果不定义webAppRootKey参数，那么webAppRootKey就是缺省的"webapp.root"--><!--此处对应log4j.properties的log4j.appender.log.File=${RootPath}/log/log.log（RootPath指日志路径）-->    <context-param>        <param-name>webAppRootKey</param-name>        <param-value>RootPath</param-value>    </context-param>    <context-param>        <param-name>log4jConfigLocation</param-name>        <param-value>classpath:log4j.properties</param-value>    </context-param>    <context-param>        <param-name>log4jRefreshInterval</param-name>        <param-value>600000</param-value>    </context-param>

（2）src下添加log4j.properties的配置文件

### 只作为参考（具体操作log4j配置说明） ###log4j.rootLogger = debug,stdout,Dlog4j.appender.stdout = org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Target = System.outlog4j.appender.stdout.layout = org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern =  %d{ABSOLUTE} %5p %c{1}:%L - %m%nlog4j.appender.D = org.apache.log4j.DailyRollingFileAppenderlog4j.appender.D.File = ../logs/log.loglog4j.appender.D.Append = truelog4j.appender.D.Threshold = DEBUGlog4j.appender.D.layout = org.apache.log4j.PatternLayoutlog4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n

（3）在java文件中直接使用

private static Logger logger = Logger.getLogger(SendMailImpl.class);logger.info("配置成功");logger.debug("配置失败"+e);

2.spring项目中log4j配置

3.java项目中log4j配置
直接在src下配置log4j.properties文件即可
java虚拟机加载log4j的类(LogManager.class)后，执行静态代码块，这个类中的静态代码块，会load log4j的配置文件，依次加载log4j.xml，log4j.properties

部分代码：

static public final String DEFAULT_CONFIGURATION_FILE = "log4j.properties";   static final String DEFAULT_XML_CONFIGURATION_FILE = "log4j.xml";  if(configurationOptionStr == null) {    url = Loader.getResource(DEFAULT_XML_CONFIGURATION_FILE); if(url == null) {   url = Loader.getResource(DEFAULT_CONFIGURATION_FILE); }