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This chapter describes the java client API for HBase that is used to perform CRUD operations on HBase tables. HBase is written in Java and has a Java Native API. Therefore it provides programmatic access to Data Manipulation Language (DML).
Class HBase Configuration
Adds HBase configuration files to a Configuration. This class belongs to the org.apache.hadoop.hbase package.
Methods and description
| S.No. | Methods and Description |
|---|---|
| 1 |
static org.apache.hadoop.conf.Configuration create() This method creates a Configuration with HBase resources. |
Class HTable
HTable is an HBase internal class that represents an HBase table. It is an implementation of table that is used to communicate with a single HBase table. This class belongs to the org.apache.hadoop.hbase.client class.
Constructors
| S.No. | Constructors and Description |
|---|---|
| 1 |
HTable() |
| 2 |
HTable(TableName tableName, ClusterConnection connection, ExecutorService pool) Using this constructor, you can create an object to access an HBase table. |
Methods and description
| S.No. | Methods and Description |
|---|---|
| 1 |
void close() Releases all the resources of the HTable. |
| 2 |
void delete(Delete delete) Deletes the specified cells/row. |
| 3 |
boolean exists(Get get) Using this method, you can test the existence of columns in the table, as specified by Get. |
| 4 |
Result get(Get get) Retrieves certain cells from a given row. |
| 5 |
org.apache.hadoop.conf.Configuration getConfiguration() Returns the Configuration object used by this instance. |
| 6 |
TableName getName() Returns the table name instance of this table. |
| 7 |
HTableDescriptor getTableDescriptor() Returns the table descriptor for this table. |
| 8 |
byte[] getTableName() Returns the name of this table. |
| 9 |
void put(Put put) Using this method, you can insert data into the table. |
Class Put
This class is used to perform Put operations for a single row. It belongs to the org.apache.hadoop.hbase.client package.
Constructors
| S.No. | Constructors and Description |
|---|---|
| 1 |
Put(byte[] row) Using this constructor, you can create a Put operation for the specified row. |
| 2 |
Put(byte[] rowArray, int rowOffset, int rowLength) Using this constructor, you can make a copy of the passed-in row key to keep local. |
| 3 |
Put(byte[] rowArray, int rowOffset, int rowLength, long ts) Using this constructor, you can make a copy of the passed-in row key to keep local. |
| 4 |
Put(byte[] row, long ts) Using this constructor, we can create a Put operation for the specified row, using a given timestamp. |
Methods
| S.No. | Methods and Description |
|---|---|
| 1 |
Put add(byte[] family, byte[] qualifier, byte[] value) Adds the specified column and value to this Put operation. |
| 2 |
Put add(byte[] family, byte[] qualifier, long ts, byte[] value) Adds the specified column and value, with the specified timestamp as its version to this Put operation. |
| 3 |
Put add(byte[] family, ByteBuffer qualifier, long ts, ByteBuffer value) Adds the specified column and value, with the specified timestamp as its version to this Put operation. |
| 4 |
Put add(byte[] family, ByteBuffer qualifier, long ts, ByteBuffer value) Adds the specified column and value, with the specified timestamp as its version to this Put operation. |
Class Get
This class is used to perform Get operations on a single row. This class belongs to the org.apache.hadoop.hbase.client package.
Constructor
| S.No. | Constructor and Description |
|---|---|
| 1 |
Get(byte[] row) Using this constructor, you can create a Get operation for the specified row. |
| 2 | Get(Get get) |
Methods
| S.No. | Methods and Description |
|---|---|
| 1 |
Get addColumn(byte[] family, byte[] qualifier) Retrieves the column from the specific family with the specified qualifier. |
| 2 |
Get addFamily(byte[] family) Retrieves all columns from the specified family. |
Class Delete
This class is used to perform Delete operations on a single row. To delete an entire row, instantiate a Delete object with the row to delete. This class belongs to the org.apache.hadoop.hbase.client package.
Constructor
| S.No. | Constructor and Description |
|---|---|
| 1 |
Delete(byte[] row) Creates a Delete operation for the specified row. |
| 2 |
Delete(byte[] rowArray, int rowOffset, int rowLength) Creates a Delete operation for the specified row and timestamp. |
| 3 |
Delete(byte[] rowArray, int rowOffset, int rowLength, long ts) Creates a Delete operation for the specified row and timestamp. |
| 4 |
Delete(byte[] row, long timestamp) Creates a Delete operation for the specified row and timestamp. |
Methods
| S.No. | Methods and Description |
|---|---|
| 1 |
Delete addColumn(byte[] family, byte[] qualifier) Deletes the latest version of the specified column. |
| 2 |
Delete addColumns(byte[] family, byte[] qualifier, long timestamp) Deletes all versions of the specified column with a timestamp less than or equal to the specified timestamp. |
| 3 |
Delete addFamily(byte[] family) Deletes all versions of all columns of the specified family. |
| 4 |
Delete addFamily(byte[] family, long timestamp) Deletes all columns of the specified family with a timestamp less than or equal to the specified timestamp. |
Class Result
This class is used to get a single row result of a Get or a Scan query.
Constructors
| S.No. | Constructors |
|---|---|
| 1 |
Result() Using this constructor, you can create an empty Result with no KeyValue payload; returns null if you call raw Cells(). |
Methods
| S.No. | Methods and Description |
|---|---|
| 1 |
byte[] getValue(byte[] family, byte[] qualifier) This method is used to get the latest version of the specified column. |
| 2 |
byte[] getRow() This method is used to retrieve the row key that corresponds to the row from which this Result was created. |
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