MAPREDUCE服务 MRS-修改HBase表:代码样例

时间：2024-11-01 09:29:12

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testModifyTable方法中。

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

    // Specify the column family name.
    byte[] familyName = Bytes.toBytes("education");
    Admin admin = null;
    try {
      // Instantiate an Admin object.
      admin = conn.getAdmin();
      // Obtain the table descriptor.
      TableDescriptor htd = admin.getTableDescriptor(tableName);

      // Check whether the column family is specified before modification.
      if (!htd.hasColumnFamily(familyName)) {
        // Create the column descriptor.
        TableDescriptor tableBuilder = TableDescriptorBuilder.newBuilder(htd) 
            .setColumnFamily(ColumnFamilyDescriptorBuilder.newBuilder(familyName).build()).build();
 

        // Disable the table to get the table offline before modifying
        // the table.
        admin.disableTable(tableName);//注[1]
        // Submit a modifyTable request.
        admin.modifyTable(tableBuilder);
        // Enable the table to get the table online after modifying the
        // table.
        admin.enableTable(tableName);
      }
      LOG.info("Modify table successfully.");
    } catch (IOException e) {
      LOG.error("Modify table failed " ,e);
    } finally {
      if (admin != null) {
        try {
          // Close the Admin object.
          admin.close();
        } catch (IOException e) {
          LOG.error("Close admin failed " ,e);
        }
      }
    }
    LOG.info("Exiting testModifyTable.");
  }

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