hbase development java

7/28/2019 HBase Development Java

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HBASE INTRODUCTIODEVELOPMENT

The term planet-size web application comes to mind, and in this


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WHAT IS IT?

It is the Hadoop database,

Sclable

Distributed

BigDatastore

Column Oriented

HBASE

HDFS

Reader


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FEATURES OF HBASE

Scalable.

Automatic failover Consistent reads and writes.

Sharding of tables

Failover support

Classes for backing Hadoop map reduce

jobs

Java API for client access

Thrift gateway and a REST Web


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WHAT IT IS NOT

No-Sql

No relation

No joins

Not a replacement of RDBMS


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NoSQL

HBase is a type of "NoSQL" database. "NoSQL" is a general term me

database isn't an RDBMS which supports SQL as its primary access langua

When we should think of using it

HBase isn't suitable for every problem. We should have lot of data,

RDBMS is better.

Difference Between HDFS and HBase

HDFS is a distributed file system that is well suited for the storage of

documentation states that it is not, however, a general purpose file system

provide fast individual record lookups in files. HBase, on the other hand, is

HDFS and provides fast record lookups (and updates) for large tables.


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THINK ONTHIS

Facebook, for example, is adding more than 15 TB, and proces

Google adding Peta-Bytes of data and processing.

Companies storing Logs, temperature details, and many other

to store and process, which come in Peta-byte for which convetechnologies will days to read the data forget about processing


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WHAT IS COLUMNS ORIENTEDMEANS Grouped by columns,

The reason to store values on a per-column basis

instead is based on the assumption that, for specific queries, not all of the values are

needed.

Reduced I/O


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COMPONENTS


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HMASTER

Master server is responsible for

monitoring all RegionServer instances in

the cluster, and is the interface for all

metadata changes, it runs on the server

which hosts namenode.

Master controls critical functions such as

RegionServer failover and completing

region splits. So while the cluster can still

run for a time without the Master, the

Master should be restarted as soon as


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ZOOKEEPER

Zookeeper is an open source software

providing a highly reliable, distributed

coordination service

Entry point for an HBase system

It includes tracking of region servers,

where the root region is hosted


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API

Interface to HBase

Using these we can we can access HBase and perform

read/write and other operation on HBase.

REST, Thrift, and Avro

Thrift API framework, for scalable cross-language

services development, combines a software stack with a

code generation engine to build services that work

efficiently and seamlessly between C++, Java, Python,

PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, JavaScript,

Node.js, Smalltalk, OCaml and Delphi and otherlan ua es.


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lib

commons-configuration-1.8.jar

commons-lang-2.6.jar

commons-logging-1.1.1.jar

hadoop-core-1.0.0.jar

hbase-0.92.1.jar

log4j-1.2.16.jar

slf4j-api-1.5.8.jar

slf4j-log4j12-1.5.8.jar

zookeeper-3.4.3.jar


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import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.HBaseConfiguration;

import org.apache.hadoop.hbase.HColumnDescriptor;

import org.apache.hadoop.hbase.HTableDescriptor;

import org.apache.hadoop.hbase.KeyValue;

import org.apache.hadoop.hbase.MasterNotRunningException;

import org.apache.hadoop.hbase.ZooKeeperConnectionException;

import org.apache.hadoop.hbase.client.Delete;

import org.apache.hadoop.hbase.client.Get;

import org.apache.hadoop.hbase.client.HBaseAdmin;

import org.apache.hadoop.hbase.client.HTable;

import org.apache.hadoop.hbase.client.Result;

import org.apache.hadoop.hbase.client.ResultScanner;

import org.apache.hadoop.hbase.client.Scan;

import org.apache.hadoop.hbase.client.Put;

import org.apache.hadoop.hbase.util.Bytes;


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Configuration hConf = HBaseConfiguration.create(conf);

hConf.set(Constants.HBASE_CONFIGURATION_ZOOKEEP

RUM, hbaseZookeeperQuorum);

hConf.set(Constants.HBASE_CONFIGURATION_ZOOKEEP

NTPORT, hbaseZookeeperClientPort); HTable hTable = new

HTable(hConf, tableName);


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/** Create a table


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/ Create a table

*/

public static void creatTable(String tableName, String[] familys)

throws Exception { HBaseAdmin adm

HBaseAdmin(conf); if (admin.tableExists(tableName)) { System.out.println

already exists!");

} else { HTableDescriptor tableDesc = new

HTableDescriptor(tableName);

for (int i = 0; i < familys.length; i++) {

tableDesc.addFamily(new

HColumnDescriptor(familys[i]));

}admin.createTable(tableDesc);

System.out.println("create table " + tableName + " o

}

/** * D l t t bl


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/** * Delete a table

*/

public static void deleteTable(String tableName) throws Exce

try {HBaseAdmin admin = new HBaseAdmin(conf);

admin.disableTable(tableName);

admin.deleteTable(tableName);

System.out.println("delete table " + tableName

} catch (MasterNotRunningException e) {

e.printStackTrace();

} catch (ZooKeeperConnectionException e) {


}

}

/**


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/

* Put (or insert) a row

*/

public static void addRecord(String tableName, String rowKe

String family, String qualifier, String value) throws Exc

try {HTable table = new HTable(conf, tableName);

Put put = new Put(Bytes.toBytes(rowKey));

put.add(Bytes.toBytes(family), Bytes.toBytes(

Bytes

.toBytes(value));

table.put(put);

System.out.println("insert recored " + rowKey

table "

+ tableName + " ok.");

} catch (IOException e) {e.printStackTrace();

/**


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/

* Delete a row

*/

public static void delRecord(String tableName, String ro

throws IOException {HTable table = new HTable(conf,

tableName);

List list = new ArrayList();

Delete del = new Delete(rowKey.getBytes());

list.add(del);

table.delete(list);

System.out.println("del recored " + rowKey + " ok

}

/**Get a row


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/ Get a row

*/

public static void getOneRecord (String tableName, String row

throws IOException{

HTable table = new HTable(conf, tableName);

Get get = new Get(rowKey.getBytes());

Result rs = table.get(get);

for(KeyValue kv : rs.raw()){

System.out.print(new String(kv.getRow()) + " " );

System.out.print(new String(kv.getFamily()) + ":" ); System.out.print(new String(kv.getQualifier()) + " " );

System.out.print(kv.getTimestamp() + " " );

System.out.println(new String(kv.getValue()));

}

}

/** Scan (or list) a table */


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public static void getAllRecord (String tableName) {

try{

HTable table = new HTable(conf, tableName);

Scan s = new Scan();

ResultScanner ss = table.getScanner(s);

for(Result r:ss){

for(KeyValue kv : r.raw()){

System.out.print(new String(kv.getRow()) + " ");

System.out.print(new String(kv.getFamily()) + ":"); System.out.pr

String(kv.getQualifier()) + " ");

System.out.print(kv.getTimestamp() + " "); System.o

String(kv.getValue())); } }

} catch (IOException e){


}

}

public static void main(String[] agrs) {


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p ( g[] g ) {

try {

String tablename = "scores";

String[] familys = { "grade", "course" };

HBaseTest.creatTable(tablename, familys);

// add record zkb

HBaseTest.addRecord(tablename, "zkb", "grade", "", "5");

HBaseTest.addRecord(tablename, "zkb", "course", "", "90");

HBaseTest.addRecord(tablename, "zkb", "course", "math", "97");

HBaseTest.addRecord(tablename, "zkb", "course", "art", "87");

// add record baoniu

HBaseTest.addRecord(tablename, "baoniu", "grade", "", "4");

HBaseTest.addRecord(tablename, "baoniu", "course", "math", "89");


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System.out.println("===========get one record========");

HBaseTest.getOneRecord(tablename, "zkb");

System.out.println("===========show all record========");

HBaseTest.getAllRecord(tablename);

System.out.println("===========del one record========");

HBaseTest.delRecord(tablename, "baoniu");


System.out.println("===========show all record========");


} catch (Exception e) {


}

}}


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hbase development java

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