import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.hbase.HBaseConfiguration;import org.apache.hadoop.hbase.HColumnDescriptor;import org.apache.hadoop.hbase.HTableDescriptor;import org.apache.hadoop.hbase.TableName;import org.apache.hadoop.hbase.client.Admin;import org.apache.hadoop.hbase.client.Connection;import org.apache.hadoop.hbase.client.ConnectionFactory;import org.apache.hadoop.hbase.util.Bytes;import org.apache.hadoop.hbase.util.Pair;import java.io.IOException;/** * 修改表结构 */public class ModifyStructOfTable {    public static void main(String args[]) throws IOException{        Configuration conf = HBaseConfiguration.create();        Connection connection = ConnectionFactory.createConnection(conf);        Admin admin = connection.getAdmin();        //        TableName tableName=TableName.valueOf("testtable2b");        //列族        HColumnDescriptor coldef1 = new HColumnDescriptor("colfam1");        //表        HTableDescriptor desc  = new HTableDescriptor(tableName).addFamily(coldef1).setValue("Description", "ModifyTableExample: Original Table");        //Create the table with the original structure and 50 regions.        admin.createTable(desc, Bytes.toBytes(1L),Bytes.toBytes(10000L),50);        //表描述        HTableDescriptor htd1 = admin.getTableDescriptor(tableName);        //列族2        HColumnDescriptor coldef2 = new HColumnDescriptor("colfam2");        //        htd1.addFamily(coldef2).setMaxFileSize(1024*1024*1024L).setValue("Description","ModifyTableExample: Modified Table");        admin.disableTable(tableName);        //更改表        admin.modifyTable(tableName,htd1);        Pair<Integer, Integer> status = new Pair<Integer, Integer>() {{            setFirst(50);            setSecond(50);        }};        for (int i = 0; status.getFirst() != 0 && i < 500; i++) {            status = admin.getAlterStatus(desc.getTableName());            if (status.getSecond() != 0) {                int pending = status.getSecond() - status.getFirst();                System.out.println(pending + " of " + status.getSecond() + " regions updated.");                try {                    Thread.sleep(1 * 1000l);                }catch (Exception e){                    System.out.println(e.getMessage());                }            } else {                System.out.println("All regions updated.");                break; }        }        if (status.getFirst() != 0) {            throw new IOException("Failed to update regions after 500 sec‐ onds.");        }        admin.enableTable(tableName);        HTableDescriptor htd2 = admin.getTableDescriptor(tableName);        System.out.println("Equals: " + htd1.equals(htd2));        System.out.println("New schema: " + htd2);    }}/** 50 of 50 regions updated. 2016-08-30 17:08:08,541 INFO  [main] client.HBaseAdmin: Started enable of testtable2b 2016-08-30 17:08:10,869 INFO  [main] client.HBaseAdmin: Enabled testtable2b Equals: true New schema: ‘testtable2b‘, {TABLE_ATT shell: ========= hbase(main):048:0> desc ‘testtable2b‘ Table testtable2b is ENABLED testtable2b, {TABLE_ATTRIBUTES => {MAX_FILESIZE => ‘1073741824‘, METADATA =http://www.mamicode.com/> {‘Description‘ => ‘ModifyTableExample: Modified Table‘}}>