清除不相关列和空值，并应用MapReduce处理

 <?xml version="1.0" encoding="UTF-8"?>

    
 <project xmlns="http://maven.apache.org/POM/4.0.0"
    
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    
      xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    
     <modelVersion>4.0.0</modelVersion>
    
  
    
     <groupId>com.henu</groupId>
    
     <artifactId>ETL</artifactId>
    
     <version>1.0-SNAPSHOT</version>
    
  
    
     <