1. log4j.properties设置如下：

   log4j.rootLogger = TRACE,stdout,file

2. public void configConstant(Constants me)也加入下面配置：

   me.setToSlf4jLogFactory();
   

3. pom.xml也加入如下依赖
   

            <!-- log4j 日志 -->

<dependency>

<groupId>log4j</groupId>

<artifactId>log4j</artifactId>

<version>1.2.17</version>

</dependency>

<!--门面-->

<dependency>

    <groupId>org.slf4j</groupId>

    <artifactId>slf4j-api</artifactId>

    <version>1.7.25</version>

</dependency>

<!--桥接器:告诉slf4j使用slf4j-simple-->

<dependency>

    <groupId>org.slf4j</groupId>

    <artifactId>slf4j-simple</artifactId>

    <version>1.7.25</version>

</dependency>

    4. 具体类中加入

       private static final Log log = Log.getLog(xxx.class);

       log.debug("debug info");

      跟进去发现isDebugEnabled始终是false