如何获取带有时间戳的HBase单元版本

  • Z时代
  • 2024-01-10
  • 分类：问答

如何使用Get.setMaxVersions（10）方法返回HBase单元的所有带时间戳的版本，其中10是任意数字（可能是20或5之类的东西）？以下是控制台的主要方法，该方法创建一个表，插入10个随机整数，然后尝试检索所有整数以打印出来。

public static void main(String[] args)
    throws ZooKeeperConnectionException, MasterNotRunningException, IOException, InterruptedException {
final String HBASE_ZOOKEEPER_QUORUM_IP = "localhost.localdomain"; //set ip in hosts file
final String HBASE_ZOOKEEPER_PROPERTY_CLIENTPORT = "2181";
final String HBASE_MASTER = HBASE_ZOOKEEPER_QUORUM_IP + ":60010";
//identify a data cell with these properties
String tablename = "characters";
String row = "johnsmith";
String family = "capital";
String qualifier = "A";
//config
Configuration config = HBaseConfiguration.create();
config.clear();
config.set("hbase.zookeeper.quorum", HBASE_ZOOKEEPER_QUORUM_IP);
config.set("hbase.zookeeper.property.clientPort", HBASE_ZOOKEEPER_PROPERTY_CLIENTPORT);
config.set("hbase.master", HBASE_MASTER);
//admin
HBaseAdmin hba = new HBaseAdmin(config);
//create a table
HTableDescriptor descriptor = new HTableDescriptor(tablename);
descriptor.addFamily(new HColumnDescriptor(family));
hba.createTable(descriptor);
hba.close();
//get the table
HTable htable = new HTable(config, tablename);
//insert 10 different timestamps into 1 record
for(int i = 0; i < 10; i++) {
    String value = Integer.toString(i);
    Put put = new Put(Bytes.toBytes(row));
    put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier), System.currentTimeMillis(), Bytes.toBytes(value));
    htable.put(put);
    Thread.sleep(200); //make sure each timestamp is different
}
//get 10 timestamp versions of 1 record
final int MAX_VERSIONS = 10;
Get get = new Get(Bytes.toBytes(row));
get.setMaxVersions(MAX_VERSIONS);
Result result = htable.get(get);
byte[] value = result.getValue(Bytes.toBytes(family), Bytes.toBytes(qualifier));  // returns MAX_VERSIONS quantity of values
String output = Bytes.toString(value);
//show me what you got
System.out.println(output); //prints 9 instead of 0 through 9
}

输出为9（因为循环在i = 9处结束，并且在Hue的HBase Browser Web

UI中看不到多个版本。我该怎么做以修复版本，以便为0-9而不是10给出单独的结果）数字9的一项结果？

回答：

您应该在Result上使用getColumnCells来获取所有版本（取决于您在Get中设置的MAX_VERSION_COUNT个）。getValue返回最新值。

样例代码：

    List<Cell> values = result.getColumnCells(Bytes.toBytes(family), Bytes.toBytes(qualifier));
    for ( Cell cell : values )
    {
        System.out.println( Bytes.toString( CellUtil.cloneValue( cell ) ) );
    }

以上是 如何获取带有时间戳的HBase单元版本 的全部内容， 来源链接： utcz.com/qa/418172.html

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