Caused by: java.lang.IllegalStateException解决办法

先贴一个完整的错误

Caused by: java.lang.IllegalStateException: Detected both log4j-over-slf4j.jar AND bound slf4j-log4j12.jar on the class path, preempting StackOverflowError. See also http://www.slf4j.org/codes.html#log4jDelegationLoop for more details.
	at org.slf4j.impl.Log4jLoggerFactory.<clinit>(Log4jLoggerFactory.java:54)
	... 13 more

然后说一下我的环境和需求，我的需求是在SpringBoot中使用Spark计算数据然后展示在前端，以下是我的maven依赖

  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>



    <!--spark-->
    <dependencies>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.11</artifactId>
            <version>2.1.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.11</artifactId>
            <version>2.1.1</version>
        </dependency>

        <!--json-->
        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

        <!--springboot-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

这里我是用了json的 ，然后就出了这个错误，这个错误的原因是：log4j-over-slf4j和slf4j-log4j12是跟java日志系统相关的两个jar包，当它们同时出现在classpath下时，就可能会引起堆栈溢出异常。因为Spring内部自带了日志依赖

明白问题所在就好解决了：在maven中加入

<!--全局排除spring-boot-starter-logging内的所有依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>*</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

去除springboot的所有日志依赖即可，如果你需要springboot的日志，就手动配置保证log4j-over-slf4j和slf4j-log4j12不要同时出现在classpath下时即可

希望对你有帮助