log4j.properties 文件的一个appender X的语法分享

    # 根日志记录器(logger)的级别定义为DEBUG并连接附加器命名为X
    log4j.rootLogger = DEBUG, X
    
    # 附加器(appender)X是定义为org.apache.log4j.FileAppender并写入到一个名为“log.out”位于日志log目录下
    log4j.appender.X=org.apache.log4j.FileAppender
    log4j.appender.X.File=${log}/log.out
    
    # 定义的布局模式是%m%n，这意味着每打印日志消息之后，将加上一个换行符
    log4j.appender.X.layout=org.apache.log4j.PatternLayout
    log4j.appender.X.layout.conversionPattern=%m%n

       public class log4jExample{
           /* Get actual class name to be printed on */
          static Logger log = Logger.getLogger(log4jExample.class.getName());
          public static void main(String[] args) throws IOException,SQLException{
              log.debug("Hello this is an debug message");
              log.info("Hello this is an info message");
           }
       }