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Monday, 2 January 2017

HBase Listing Table Tutorial


Listing a Table using HBase Shell
     list is the command that is used to list all the tables in HBase. Given below is the syntax of the list command.
hbase> list
     When you type this command and execute in HBase prompt, it will display the list of all the tables in HBase as shown below.
hbase> list
TABLE
emp
Listing Tables Using Java API
     We have a method called listTables() in the class HBaseAdmin to get the list of all the tables in HBase. This method returns an array of HTableDescriptor objects.
Example
package com.ashok.hbase;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.MasterNotRunningException;
import org.apache.hadoop.hbase.client.HBaseAdmin;

public class ListTables {
   public static void main(String args[])throws MasterNotRunningException, IOException{

      // Instantiating a configuration class
      Configuration conf = HBaseConfiguration.create();

      // Instantiating HBaseAdmin class
      HBaseAdmin admin = new HBaseAdmin(conf);

      // Getting all the list of tables using HBaseAdmin object
      HTableDescriptor[] tableDescriptor = admin.listTables();

      // printing all the table names.
      for (int i=0; i<tableDescriptor.length;i++ ){
         System.out.println(tableDescriptor[i].getNameAsString());
      }
   }
}

Next Tutorial  HBase Disabling a Table Tutorial

Previous Tutorial  HBase Create Table Tutorial

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