Caused by: java.lang.ClassCastException: class java.lang.Double cannot be cast to class org.apache.hadoop.io.WritableComparable

错误：

Caused by: java.lang.ClassCastException: class java.lang.Double cannot be cast to class org.apache.hadoop.io.WritableComparable (java.lang.Double is in module java.base of loader 'bootstrap'; org.apache.hadoop.io.WritableComparable is in unnamed module of loader 'app')

 

 

 原因：

          在写Comparator时方法写错了，还导错了包

         

 

     解决：  应该改为

         

           导入这两个包