使用过滤器Filter

功能简介

HBase Filter主要在Scan和Get过程中进行数据过滤，通过设置一些过滤条件来实现，如设置RowKey、列名或者列值的过滤条件。

具体过滤条件根据用户使用场景选取。

代码样例

public void testSingleColumnValueFilter() {
  LOG.info("Entering testSingleColumnValueFilter.");
  Table table = null;
  ResultScanner rScanner = null;

  try {
    table = conn.getTable(tableName);
    Scan scan = new Scan();
    scan.addColumn(Bytes.toBytes("info"), Bytes.toBytes("name"));
    // Set the filter criteria.
    SingleColumnValueFilter filter = new SingleColumnValueFilter(
        Bytes.toBytes("info"), Bytes.toBytes("name"), CompareOp.EQUAL,
        Bytes.toBytes("I"));
    scan.setFilter(filter);
    // Submit a scan request.
    rScanner = table.getScanner(scan);
    // Print query results.
    for (Result r = rScanner.next(); r != null; r = rScanner.next()) {
      for (Cell cell : r.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("Single column value filter successfully.");
  } catch (IOException e) {
    LOG.error("Single column value filter failed " ,e);
  } finally {
      if (rScanner != null) {
          // Close the scanner object.
          rScanner.close();
        }
    if (table != null) {
      try {
        // Close the HTable object.
        table.close();
      } catch (IOException e) {
        LOG.error("Close table failed " ,e);
      }
    }
  }
  LOG.info("Exiting testSingleColumnValueFilter.");
}