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Operations using Java API

 

1. Create table using Java API

createTable() method is used to create a table using java API.

 Example:- 

import java.io.IOException;

import org.apache.hadoop.hbase.*;

import org.apache.hadoop.conf.Configuration;

public class tablecreate {

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create(); // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(c);      // Instantiate HbaseAdmin class

// Instantiate table descriptor class

HTableDescriptor tdescriptor = new TableDescriptor(TableName.valueOf("student"));

tdescriptor.addFamily(new HColumnDescriptor("id"));  // Add column families to tdescriptor

 ad.createTable(tdescriptor);   // Execute table using ad

System.out.println(" Table is created "); // It will print “Table is created”

}

}

Compile and execute the program. Then after this it will show the output i.e.

Table is created

 

2. Disable the table using java API

isTableDisabled()  method is used to check that table is disabled or not. If table is disabled then it will return true otherwise false.If table is not diabled then disableTable() method is used.

Example:- 

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class TableDisable{

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

Configuration c= HBaseConfiguration.create();      // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(c);      // Instantiate HBaseAdmin class

Boolean boolean = admin.isTableDisabled("student");      // Verifying weather the table is disabled

System.out.println(boolean);

if(!boolean){

ad.disableTable("student");      // Disabe the table using HBaseAdmin object

System.out.println("Table is disabled"); // It will print “Table is disabled”

}

}

}

Compile and execute the program. Then after this it will show the output i.e.

Table is disabled

 

3. Listening of table using Java API

For this listTables() method is used.

 Example:-

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class TablesList {

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

Configuration c = HBaseConfiguration.create();      // Instantiate a configuration class

HBaseAdmin ad = new HBaseAdmin(c);   // Instantiate HBaseAdmin class

HTableDescriptor[] tDescriptor = ad.listTables(); //  Give list of tables HBaseAdmin Object

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

System.out.println(tDescriptor[k].getNameAsString());      // Print all the table names.

}

}

}

Compile and execute the program. Then after this it will show the output i.e.

User

Student

 

4. Enable a Table Using Java API

isTableEnabled()  method is used to check that table is enabled or not. If table is enabled then it will return true otherwise false.If table is not enabled then enableTable() method is used.

Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.*;

public class TableEnable{

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

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(c);   // Instantiate HBaseAdmin class

Boolean boolean = ad.isTableEnabled("student");      //check whether the table is enabled

System.out.println(boolean);

if(!boolean){

ad.enableTable("student");

System.out.println("Table is Enabled");     // Enable the table using HBaseAdmin object

}

}

}

Compile and execute the program. Then after this it will show the output i.e.

Table is Enabled

 

5. Exit HBase Using Java API 

For this shutdown() method  is used.

Example:-

 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class ShutDownHbase{

public static void main(String args[])throws IOException {

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(c); // Instantiate HBaseAdmin class

System.out.println("Shut down HBase");   // Shut down HBase

ad.shutdown();

}

}

Compile and execute the program. Then after this it will show the output i.e.

Shut down HBase

 

6. Add Column Family Using Java API

For this, addColumn() method is used.

 Example:-

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class ColumnAdd{

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

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class.

HBaseAdmin ad = new HBaseAdmin(c); // Instantiate HBaseAdmin class.

HColumnDescriptor cDescriptor = new HColumnDescriptor("id"); //Instantiate columnDescriptor

ad.addColumn("student", cDescriptor);      // Add column family

System.out.println("coloumn is  added which name is id");

}

}

Compile and execute the program. Then after this it will show the output i.e.

coloumn is  added which name is id

 

7. Deleting a Column Family Using Java API 

For this, deleteColumn() method is used.

Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class ColoumnDelete{

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

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class.

HBaseAdmin ad = new HBaseAdmin(c);      // Instantiate HBaseAdmin class.

ad.deleteColumn("student","id");  // Deleting a column family

System.out.println("coloumn  is deleted which name is id");

}

}

Compile and execute the program. Then after this it will show the output i.e.

coloumn is  deleted which name is id

 

8. Check the existence of a table using java API-

This can be done by tableExists() method.

 Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class TableExists{

public static void main(String args[])throws IOException{

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(c);      // Instantiate HBaseAdmin class

Boolean boolean = ad.tableExists("student");       // Cheking the existance of the table

System.out.println( boolean);

}

}

Compile and execute the program. Then after this it will show the output i.e.

If table is exists the it return true otherwise false

 

9. Drop a table using Java API:-

For this first we need to disable the table then delete the table using  deleteTable() method.

Example:-

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class TableDelete {

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create();      // Instantiate configuration class

HBaseAdmin ad = new HBaseAdmin(conf);      // Instantiate HBaseAdmin class

ad.disableTable("student");       // disable the table

ad.deleteTable("student");  // Delete the table

System.out.println("Table is deleted which name is student");

}

}

Compile and execute the program. Then after this it will show the output i.e.

Table is deleted which name is student

 

10. Insert data using Java API

Put() method is used to save the data whereas add() method is used to add the data.

Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class DataInsert{

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create(); // Instantiate Configuration class

HTable hTable = new HTable(c, "student");       // Instantiate HTable class

Put P1 = new Put(Bytes.toBytes("row1"));  // Instantiate put Class

// accepts column family name, row name  and its value

P1.add(Bytes.toBytes("college"),   Bytes.toBytes("id"),Bytes.toBytes("20"));

P1.add(Bytes.toBytes("college"),Bytes.toBytes("name"),Bytes.toBytes("rishi"));

hTable.put(P1);

System.out.println("Data is inserted");       // Save the put Instance to the HTable.

hTable.close();      // close HTable

}

}

Compile and execute the program. Then after this it will show the output i.e.

Data is inserted

 

11. Delete Data Using Java API

This can be done by using delete() method.

Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class DataDelete {

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create();// Instantiate Configuration class

HTable table = new HTable(c, "student");       // Instantiate HTable class

Delete delete = new Delete(Bytes.toBytes("row1"));       // Instantiating Delete class

delete.deleteColumn(Bytes.toBytes("college"), Bytes.toBytes("id"));

table.delete(delete);        // delete the data

table.close();        // close the HTable object

System.out.println("Data  is deleted");

}

}

Compile and execute the program. Then after this it will show the output i.e.

Data is deleted

 

12. Read Data using Java API

This can be done by using get() method.

Example:- 

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class DataRead{

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create();      // Instantiate Configuration class

HTable table = new HTable(c, "student"); // Instantiate HTable class

Get g = new Get(Bytes.toBytes("row1"));        // Instantiate Get class

Result result = table.get(g);      // Read the data

// Read values from Result class object

byte [] value = result.getValue(Bytes.toBytes("college"),Bytes.toBytes("name"));

String name = Bytes.toString(value);      // Print the values

System.out.println("name: " + name);

}

}

Compile and execute the program. Then after this it will show the output i.e.

name: rishi

 

13. Update Data using Java API

This can be done using put() method.

Example:-

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class DataUpdate{

public static void main(String[] args) throws IOException {

Configuration c = HBaseConfiguration.create();      // Instantiate Configuration class

HTable hTable = new HTable(c, "student");       // Instantiate HTable class

Put P1 = new Put(Bytes.toBytes("row1"));   // Instantiate Put class

P1.add(Bytes.toBytes("college"),  Bytes.toBytes("name"),Bytes.toBytes("raj")); //update the data

hTable.put(P1);      // Save the put Instance to the HTable.

System.out.println("Data is updated");

hTable.close();      // close HTable

}

}

Compile and execute the program. Then after this it will show the output i.e.

Data is updated

 

14. Scan Using Java API

Example:-

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.*;

public class tableScan{

public static void main(String args[]) throws IOException{

Configuration c = HBaseConfiguration.create();        // Instantiate Configuration class

HTable table = new HTable(c, "student");        // Instantiate HTable class

Scan scan = new Scan();      // Instantiate the Scan class

scan.addColumn(Bytes.toBytes("college"), Bytes.toBytes("name"));  // Scan the required columns

ResultScanner scanner = table.getScanner(scan);      // Get scan result

// Reading values from scan result

for (Result result = scanner.next(); result != null; result = scanner.next())

System.out.println("Result Found: " + result);

scanner.close();      //close the scanner

}

}

Compile and execute the program. Then after this it will show the output i.e.

Result Found:
keyvalues={row1/college::name/15162756234/Put/vlen=5/mvcc=0}

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