maven mybatis 打印sql问题

<dependency>  
    <groupId>org.slf4j</groupId>  
    <artifactId>slf4j-log4j12</artifactId>  
    <version>1.7.21</version>  
</dependency>  
  
<dependency>  
    <groupId>org.slf4j</groupId>  
    <artifactId>slf4j-api</artifactId>  
    <version>1.7.21</version>  
</dependency>  

有slf4j，则必须要有slf4j-log4j12