MapReduce服务 MRS-使用Scan读取数据:代码样例

时间：2023-11-01 16:19:45

MapReduce服务 MRS

代码样例

以下代码片段在com.huawei.bigdata.hbase.examples包的“HBaseSample”类的testScanData方法中。

public void testScanData() {    LOG.info("Entering testScanData.");    Table table = null;     // Instantiate a ResultScanner object.    ResultScanner rScanner = null;    try {      // Create the Configuration instance.      table = conn.getTable(tableName);      // Instantiate a Get object.      Scan scan = new Scan();      scan.addColumn(Bytes.toBytes("info"), Bytes.toBytes("name"));      // Set the cache size.      scan.setCaching(1000);      // 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("Scan data successfully.");    } catch (IOException e) {      LOG.error("Scan data 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 testScanData.");  }

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