Zookeeper包中，slf4j-log4j12和log4j冲突问题解决

程序启动时会有日志警告

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/E:/maven/mavenRepository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/E:/maven/mavenRepository/org/slf4j/slf4j-log4j12/1.7.26/slf4j-log4j12-1.7.26.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
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.

主要是因为Zookeeper包中，slf4j-log4j12和log4j冲突了，需要处理一下

在服务提供者和消费中的pom.xml文件的ZooKeeper依赖中添加如下内容

<dependency>
   <groupId>com.101tec</groupId>
   <artifactId>zkclient</artifactId>
   <version>0.10</version>
          <exclusions>
              <exclusion>
                  <groupId>log4j</groupId>
                  <artifactId>log4j</artifactId>
              </exclusion>
              <exclusion>
                  <groupId>org.slf4j</groupId>
                  <artifactId>slf4j-log4j12</artifactId>
              </exclusion>
          </exclusions>
</dependency>

这样警告就会消失了。