IDEA：No SLF4J providers were found.

如果您是用IDEA 的 maven 写的

将slf4j的导入包 更改 为下列代码

         <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.8.0-beta2</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.8.0-beta2</version>
            <scope>test</scope>
        </dependency>

原因如下：

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No SLF4J providers were found.
This warning, i.e. not an error, message is reported when no SLF4J providers could be found on the class path. Placing one (and only one) of slf4j-nop.jar slf4j-simple.jar, slf4j-log4j12.jar, slf4j-jdk14.jar or logback-classic.jar on the class path should solve the problem. Note that these providers must target slf4j-api 1.8 or later.

In the absence of a provider, SLF4J will default to a no-operation (NOP) logger provider.

Please note that slf4j-api version 1.8.x and later use the ServiceLoader mechanism. Earlier versions relied on the static binder mechanism which is no longer honored by slf4j-api. Please read the FAQ entry What has changed in SLF4J version 1.8.0? for further important details.

If you are responsible for packaging an application and do not care about logging, then placing slf4j-nop.jar on the class path of your application will get rid of this warning message. Note that embedded components such as libraries or frameworks should not declare a dependency on any SLF4J providers but only depend on slf4j-api. When a library declares a compile-time dependency on a SLF4J provider, it imposes that provider on the end-user, thus negating SLF4J's purpose.