Log4j 的配置和使用

1、log4j.properties

		# Log4j提供的 appender 有以下几种：
		# org.apache.log4j.ConsoleAppender(控制台)
		# org.apache.log4j.FileAppender(文件)
		# org.apache.log4j.DailyRollingFileAppender(每天产生一个日志文件)
		# org.apache.log4j.RollingFileAppender(文件大小达到指定的尺寸时产生新的文件)
		# org.apache.log4j.WriterAppender(将日志信息以流格式发送到任意指定的地方)
		
		log4j.rootLogger=debug, stdout, R
		
		log4j.appender.stdout=org.apache.log4j.ConsoleAppender
		log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
		
		# Pattern to output the caller's file name and line number.
		log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n
		
		# 当文件达到指定大小时产生新的日志文件
		log4j.appender.R=org.apache.log4j.RollingFileAppender
		# 设置生成的文件的名称
		log4j.appender.R.File=example.log
		
		# 设置生成的日志文件大小
		log4j.appender.R.MaxFileSize=1KB
		# 设置保存日志的文件数量
		log4j.appender.R.MaxBackupIndex=10000
		
		log4j.appender.R.layout=org.apache.log4j.PatternLayout
		log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n

 

2、非 web 环境使用log4j。初始化 log4j的 Demo

				public class Demo {
					private static final String propertiesFileName = "/log4j.properties";
					private static Logger logger = Logger.getLogger(Demo.class);
					
					/**
					 * 初始化log4j
					 * @return Boolean 
					 */
					private static boolean initLog4j() {
						boolean flag = true;
						InputStream inputStream = Demo.class
								.getResourceAsStream(propertiesFileName);
						Properties prop = new Properties();
						try {
							prop.load(inputStream);
							PropertyConfigurator.configure(prop);
						} catch (IOException e) {
							flag = false;
							e.printStackTrace();
						}
				
						return flag;
					}
				
					public static void main(String[] args) {
						boolean flag = initLog4j();
						for (int i = 0; i < 100; i++) {
							logger.info("hello");
							System.out.println(flag);
						}
					}
				
				}