log4j的使用

朴灿烈づ我的快乐病毒、 2023-06-02 03:19 5阅读 0赞

今天先简单学了下，在maven的java项目中如何使用log4j。以后有时间再研究如何跟springMVC的集成

使用log4j，大概需要分3步吧：

1、首先需要jar包引入，用maven吧简单方便

![1078922-20170126104758316-955865585.png][]

2、配置log4j.properties文件，无非指定三个：日志级别、输出目的地、日志格式

![1078922-20170126105123894-667950242.png][]

#log level & appender
    log4j.rootLogger=DEBUG,A1,R
    # ConsoleAppender 输出
    log4j.appender.A1=org.apache.log4j.ConsoleAppender
    log4j.appender.A1.layout=org.apache.log4j.PatternLayout
    log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss,SSS} [%c]-[%p] %m%n
    #to file
    log4j.appender.R=org.apache.log4j.DailyRollingFileAppender
    log4j.appender.R.File=logs/log.log
    log4j.appender.R.layout=org.apache.log4j.PatternLayout
    log4j.appender.R.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} [%t] [%c] [%p] - %m%n

3、测试类中使用：Logger.getLogger

import org.apache.log4j.Logger;
    import org.apache.log4j.PropertyConfigurator;
    
    /**
     * Created by danny.yao on 2017/1/26.
     */
    public class Test {
        private static Logger logger = Logger.getLogger(Test.class.getName());
    
        public static void main(String[] args){
    //        PropertyConfigurator.configure("log4j.properties");
            logger.debug("debug///,,,,,");
            logger.info("info......");
            logger.error("error.......!!!!!1");
        }
    }

运行，在console可以看到日志，同时在生成logs/log.log文件

![1078922-20170126105442441-1854267633.png][]

![1078922-20170126105511769-2019219321.png][]

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**坑：**代码中不需要手动去加载配置文件PropertyConfigurator.configure("log4j.properties")，不然反而会报错

不明所以，只是看到这篇文章这么说的：[http://blog.csdn.net/guochunyang/article/details/46984691][http_blog.csdn.net_guochunyang_article_details_46984691]

![1078922-20170126105814706-3290090.png][]

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这篇对log4j说得比较详细，可参考：[log4j.properties 使用说明][log4j.properties]

转载于:https://www.cnblogs.com/dannyyao/p/6351366.html

[1078922-20170126104758316-955865585.png]: /images/20230601/adf98ecca3494c828a8f6b5e91e1600d.png
[1078922-20170126105123894-667950242.png]: /images/20230601/d0169d39d7724e3c81e98bef485c7e59.png
[1078922-20170126105442441-1854267633.png]: /images/20230601/4092ab75921f41efa5b947026988253b.png
[1078922-20170126105511769-2019219321.png]: /images/20230601/35447c0a5b16489b9cc59a498c775e79.png
[http_blog.csdn.net_guochunyang_article_details_46984691]: http://blog.csdn.net/guochunyang/article/details/46984691
[1078922-20170126105814706-3290090.png]: /images/20230601/a1ab2929cbd548d5a20af283a05c51f5.png
[log4j.properties]: http://www.blogjava.net/hwpok/archive/2008/01/16/175711.html