Reading Data Using Get

Function Description

Before reading data from a table, create a table instance and a Get object. You can also set parameters for the Get object, such as the column family name and column name. Query results are stored in the Result object that stores multiple Cells.

Sample Code

The following code snippets are in the testGet method in the HBaseExample class of the com.huawei.bigdata.hbase.examples packet.

public void testGet() {
    LOG.info("Entering testGet.");

    // Specify the column family name.
    byte[] familyName = Bytes.toBytes("info");
    // Specify the column name.
    byte[][] qualifier = {Bytes.toBytes("name"), Bytes.toBytes("address")};
    // Specify RowKey.
    byte[] rowKey = Bytes.toBytes("012005000201");

    Table table = null;
    try {
        // Create the Configuration instance.
        table = conn.getTable(tableName);

        // Instantiate a Get object.
        Get get = new Get(rowKey);

        // Set the column family name and column name.
        get.addColumn(familyName, qualifier[0]);
        get.addColumn(familyName, qualifier[1]);

        // Submit a get request.
        Result result = table.get(get);

        // Print query results.
        for (Cell cell : result.rawCells()) {
            LOG.info(Bytes.toString(CellUtil.cloneRow(cell)) + ":"
                + Bytes.toString(CellUtil.cloneFamily(cell)) + ","
                + Bytes.toString(CellUtil.cloneQualifier(cell)) + ","
                + Bytes.toString(CellUtil.cloneValue(cell)));
        }
        LOG.info("Get data successfully.");
    } catch (IOException e) {
        LOG.error("Get data failed ", e);
    } finally {
        if (table != null) {
            try {
                // Close the HTable object.
                table.close();
            } catch (IOException e) {
                LOG.error("Close table failed ", e);
            }
        }
    }
    LOG.info("Exiting testGet.");
}