17.log4j.properties例子:log4j.appender.file.DatePattern

package com.v512.log4j;

import org.apache.log4j.Logger;

public class HelloLog4J {
	// 构造记录器,形参是记录器所在的类,表示要在该类做日志
	private static Logger logger = Logger.getLogger(HelloLog4J.class);
	/** 
	 * @param args
	 */
	public static void main(String[] args) {
		getMessage();
	}
	
	private static void getMessage() {
		// 记录下各种级别的信息,这些信息放在哪儿,以哪种方式存放,在log4j.properties文件中配置.
		logger.debug("This is debug message.");
		logger.info("This is a info message.");
		logger.warn("This is a warn message.");
		logger.error("This is a error message.............");
	}

}
package com.v512.log4j;

import org.apache.log4