使用HBase Shell扫描
扫描命令用于查看HTable中的数据.使用scan命令，您可以获取表数据.其语法如下:
scan'< table name>'
示例
以下示例说明如何使用scan命令从表中读取数据.这里我们正在阅读 emp 表.
hbase(main):010:0> scan 'emp'ROW COLUMN + CELL1 column = personal data:city, timestamp = 1417521848375, value = hyderabad 1 column = personal data:name, timestamp = 1417521785385, value = ramu1 column = professional data:designation, timestamp = 1417585277,value = manager1 column = professional data:salary, timestamp = 1417521903862, value = 500001 row(s) in 0.0370 seconds
使用Java API扫描
扫描整个表的完整程序使用java API的数据如下.
import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.hbase.HBaseConfiguration;import org.apache.hadoop.hbase.util.Bytes;import org.apache.hadoop.hbase.client.HTable;import org.apache.hadoop.hbase.client.Result;import org.apache.hadoop.hbase.client.ResultScanner;import org.apache.hadoop.hbase.client.Scan;public class ScanTable{ public static void main(String args[]) throws IOException{ // Instantiating Configuration class Configuration config = HBaseConfiguration.create(); // Instantiating HTable class HTable table = new HTable(config, "emp"); // Instantiating the Scan class Scan scan = new Scan(); // Scanning the required columns scan.addColumn(Bytes.toBytes("personal"), Bytes.toBytes("name")); scan.addColumn(Bytes.toBytes("personal"), Bytes.toBytes("city")); // Getting the scan result ResultScanner scanner = table.getScanner(scan); // Reading values from scan result for (Result result = scanner.next(); result != null; result = scanner.next()) System.out.println("Found row : " + result); //closing the scanner scanner.close(); }}编译并执行上述程序，如下所示.
$ javac ScanTable.java $ java ScanTable
以下应该是输出:
Found row :keyvalues={row1/personal:city/1418275612888/Put/vlen=5/mvcc=0,row1/personal:name/1418035791555/Put/vlen=4/mvcc=0}