HBase common operating JAVA API

In order to facilitate future viewing, we summarize some of the commonly used operating hbase java code:

package com.mcq;

import static org.hamcrest.CoreMatchers.describedAs;
import static org.hamcrest.CoreMatchers.nullValue;

import java.io.IOException;
import java.io.PushbackInputStream;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellScannable;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
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.Table;
import org.apache.hadoop.hbase.util.Bytes;

public class TestHbase {
	private static Admin admin = null;
	private static Connection connection = null;
	private static Configuration conf = null;
	static {
		// HBase profile
		conf = HBaseConfiguration.create();
		conf.set("hbase.zookeeper.quorum", "192.168.1.103");
		// Get the connection object
		try {
			connection = ConnectionFactory.createConnection(conf);
			// Get the object HBase administrator
			admin = connection.getAdmin();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace ();
		}
	}

	private static void close(Connection conn, Admin admin) throws IOException {
		if (conn != null) {
			conn.close();
		}
		if (admin != null) {
			admin.close();
		}
	}

	// determine whether there is table
	public static boolean tableExist(String tableName) throws IOException {
		boolean tableExists = admin.tableExists(TableName.valueOf(tableName));
		return tableExists;
	}

	// Create a table
	public static void createTable(String tableName, String... cfs) throws IOException {
		if (tableExist(tableName)) {
			System.out.println ( "table already exists");
			return;
		}
		// cfs is a column family, the official suggested a table one, but can have multiple
		// Create a table descriptor
		HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));
		for (String cf : cfs) {
			// create a column descriptor
			HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf);
// hColumnDescriptor.setMaxVersions (3); // set the number of versions
			hTableDescriptor.addFamily(hColumnDescriptor);
		}
		// Create the operating table
		admin.createTable(hTableDescriptor);
	}

	// Delete table
	public static void deleteTable(String tableName) throws IOException {
		if (!tableExist(tableName)) {
			System.out.println ( "table does not exist");
			return;
		}
		// make unusable table (offline)
		admin.disableTable(TableName.valueOf(tableName));
		// delete operation
		admin.deleteTable(TableName.valueOf(tableName));
		System.out.println ( "table deleted");
	}

	// add, change
	public static void putData(String tableName, String rowKey, String cf, String cn, String value) throws IOException {
		// Get the table object
//		HTable table=new HTable(conf,TableName.valueOf(tableName)); 已过时
		Table table = connection.getTable(TableName.valueOf(tableName));
		// Create Object put
		Put put = new Put(Bytes.toBytes(rowKey));
		// adding data
		put.addColumn(Bytes.toBytes(cf), Bytes.toBytes(cn), Bytes.toBytes(value));
		// add operation
		table.put(put);
	}

	// delete
	public static void delete(String tableName, String rowKey, String cf, String cn) throws IOException {
		// get table objects
		Table table = connection.getTable(TableName.valueOf(tableName));
		// Create delete objects
		Delete delete = new Delete (Bytes.toBytes (rowKey)); // Delete the entire column family
		delete.addColumns (Bytes.toBytes (cf), Bytes.toBytes (cn)); // delete all versions
// delete.addColumn (Bytes.toBytes (cf), Bytes.toBytes (cn)); not recommended, delete only the latest version
		// delete operation
		table.delete(delete);
		table.close();
	}

	// check - a full table scan, you can only get the latest version
	public static void scanTable(String tableName) throws IOException {
		// get table objects
		Table table = connection.getTable(TableName.valueOf(tableName));
		// build Scanner
		Scan scan = new Scan();
		ResultScanner resultScanner = table.getScanner(scan);

		// traverse the data and print
		for (Result result : resultScanner) { // rowkey
			Cell[] cells = result.rawCells();
			for (Cell cell : cells) { // cell
				System.out.println("RK:" + Bytes.toString(CellUtil.cloneRow(cell)) + ",CF:"
						+ Bytes.toString(CellUtil.cloneFamily(cell)) + ",CN:"
						+ Bytes.toString(CellUtil.cloneQualifier(cell)) + ",VALUE:"
						+ Bytes.toString(CellUtil.cloneValue(cell)));
			}
		}
		table.close();
	}

	// check - Gets the designated column family
	public static void getData(String tableName, String rowKey, String cf, String cn) throws IOException {
		Table table = connection.getTable(TableName.valueOf(tableName));
		Get get = new Get(Bytes.toBytes(rowKey));
		get.addColumn(Bytes.toBytes(cf), Bytes.toBytes(cn));
//		get.addFamily(cf);
// get.setMaxVersions (); // default parameters are not transmitted within the table structure maxversions
		get.setMaxVersions(2);
		Result result = table.get(get);
		Cell[] cells = result.rawCells();
		for (Cell cell : cells) { // cell
			System.out.println("RK:" + Bytes.toString(CellUtil.cloneRow(cell)) + ",CF:"
					+ Bytes.toString(CellUtil.cloneFamily(cell)) + ",CN:"
					+ Bytes.toString(CellUtil.cloneQualifier(cell)) + ",VALUE:"
					+ Bytes.toString(CellUtil.cloneValue(cell)));
		}
	}

	public static void main(String[] args) throws IOException {
		// determine whether there is table
//		System.out.println(tableExist("student"));
//		System.out.println(tableExist("staff"));

		// Create a table
//		createTable("staff", "info");
//		System.out.println(tableExist("staff"));

		// Delete table
//		deleteTable("staff");

		// add, change
//		putData("student", "1001", "info", "name", "mcq");

		// delete
//		delete("student", "1001", "info", "name");

		// check - a full table scan
//		scanTable("student");

		// check - Gets the designated column family
		getData("student", "1001","info","name");
		
		// Close the resource
		close(connection, admin);
	}
}