hbase Using the Java API
Syntax
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HBaseConfiguration.create(); //Create a configuration file
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Configuration.set(String key, String value); //Add a key to the configuration
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ConnectionFactory.createConnection(HBaseConfiguration configuration); //Connects to HBase
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Connection.getAdmin(); //Instanciate a new Admin
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new HTableDescriptor(Table.valueOf(String tableName));; //Create a table descriptor
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HTableDescriptor.addFamily(new HColumnDescriptor(String familyName)); //Add a family to the table descriptor
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Admin.createTable(HTableDescriptor descriptor); //Create a table as described in the descriptor
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Admin.deleteTable(TableName.valueOf(String tableName)); //Delete a table
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Connection.getTable(TableName.valueOf(String tableName)); //Get a Table Object
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new Get(Bytes.toBytes(String row_key)); //Create a new Get
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table.get(Get get) //Returns a Result
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new Put(String row_key); //Create a new Put
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table.put(Put put); //Insert the row(s)
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new Scan(); //Create new Scan
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table.getScanner(Scan scan); //Return a ResultScanner
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new Delete(Bytes.toBytes(String row_key)); //Create a new Delete
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table.delete(Delete delete); //Delete a row from the table
Parameters
| Parameter | Possible Values |
|---|---|
| CompareOp | CompareOp.EQUAL , CompareOp.GREATER , CompareOp.GREATER_OR_EQUAL , CompareOp.LESS , CompareOp.LESS_OR_EQUAL , CompareOp.NOT_EQUAL , CompareOp.NO_OP (no operation) |
Remarks
This topic show various examples of how to use the Java API for HBase. In this topic you will learn to create and delete a table, insert, query and delete rows from a table but also use the Scans filters.
You will notice than many methods of this API take Bytes as parameters for example the columnFamily name, this is due to HBase implementation. For optimization purpose, instead of storing the values as String, Integer or whatever, it stores a list of Bytes, that is why you need to parse all those values as Bytes. To do this, the easiest method is to use Bytes.toBytes(something).
Please feel free to notice if you see any mistake or misunderstanding.
