title: How to retrieve information from specific rows from table in Hbase?
body: <p>I have a table in Hbase and the key of this table is "user_name" + "id" for example ("username123"). 
  I want to retrieve all rows for specific user_name for example (if i have some rows with key "john1","john2"..., i want to retrieve all rows for john)
  How can i do it ?</p>