maven依賴:

<dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-nop</artifactId>
            <version>1.8.0-beta1</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId
 
>slf4j-simple</artifactId>
            <version>1.8.0-beta1</version>
        </dependency>

啟動警告:

SLF4J: Class path contains multiple SLF4J providers.
SLF4J: Found provider [org.slf4j.helpers.NOPServiceProvider@4aa8f0b4]
SLF4J: Found provider [org.slf4j.simple.SimpleServiceProvider
 
@7960847b]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual provider is of type [org.slf4j.helpers.NOPServiceProvider@4aa8f0b4]

原因是maven進行管理專案的時候,多添加了SLF4J providers的依賴,事實上provider is nop,所以把simple去掉就ok了
改為:

<dependency>
            <groupId>
 
org.slf4j</groupId>
            <artifactId>slf4j-nop</artifactId>
            <version>1.8.0-beta1</version>
        </dependency>

更改後maven會提示更新依賴

==>點選import changes