最近在開發過程使用到log4j，在使用過程中遇到一個問題，如下：

log4j:WARN No appenders could be foundfor logger (com.jc.UpgradeImage.UpgradeImage).

log4j:WARN Please initialize the log4jsystem properly.

log4j:WARN Seehttp://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

import org.apache.log4j.Logger;

importorg.apache.log4j.PropertyConfigurator; 

public class UpgradeImage {

         privatestatic Logger logger = Logger.getLogger(UpgradeImage.class);  

         publicstatic void main(String[] args) {

                   //TODO Auto-generated method stub

             logger.debug("debug");

             logger.info("This is info  message.");  

         }

}
 

經過查詢資料，發現有兩種解決方式，現總結如下：

1.修改原始碼，增加一行程式碼，

package com.jc.UpgradeImage;

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class UpgradeImage {
	private static Logger logger =  Logger.getLogger(UpgradeImage.class);   
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		<span style="color:#FF6666;">PropertyConfigurator.configure("log4j.properties");</span>
	    logger.debug("debug");
	    logger.info("This is info  message.");   
	}
}