idea dubbo工程中使用了logback输出日志，启动provider服务和consumer服务时报错 问题解决

问题描述：控制台中异常信息如下：

log4j:WARN No appenders could be found for logger (com.alibaba.dubbo.common.logger.LoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

解决办法：

在引入的dubbo的依赖中需要要排除对log4j的依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.5</version>
    
    <exclusions>
        <exclusion>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
        </exclusion>
    </exclusions>
</dependency>

问题解决！

另外启动consumer服务即web时 还会报错如下：

ERROR StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath. Using SimpleLogger to log to the console...

解决方法：

在web的pom.xml中添加如下依赖
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-to-slf4j</artifactId>
    <version>2.8.2</version>
</dependency>