📜  HBase-客户端API

📅  最后修改于: 2020-11-30 04:18:18             🧑  作者: Mango


本章介绍了用于HBase的Java客户端API,该API用于对HBase表执行CRUD操作。 HBase用Java编写,并具有Java本机API。因此,它提供对数据处理语言(DML)的编程访问。

HBase类配置

将HBase配置文件添加到配置中。此类属于org.apache.hadoop.hbase包。

方法与说明

S.No. Methods and Description
1

static org.apache.hadoop.conf.Configuration create()

This method creates a Configuration with HBase resources.

HTable类

HTable是代表HBase表的HBase内部类。它是表的实现,用于与单个HBase表进行通信。该类属于org.apache.hadoop.hbase.client类。

建设者

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.

方法与说明

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.

类推

此类用于对单行执行Put操作。它属于org.apache.hadoop.hbase.client软件包。

建设者

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.

方法

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.

类获取

此类用于在单行上执行Get操作。此类属于org.apache.hadoop.hbase.client软件包。

建设者

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)

方法

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.

类删除

此类用于在单行上执行Delete操作。要删除整行,请使用要删除的行实例化Delete对象。此类属于org.apache.hadoop.hbase.client软件包。

建设者

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.

方法

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.

班级成绩

此类用于获取Get或Scan查询的单行结果。

建设者

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().

方法

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.