HBase-建表(普通建表及预分区建表)

package com.hbase.HBaseAdmin;import java.io.IOException;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.client.RegionLocator;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Pair;/**
* @author:FengZhen
* @create:2018年9月6日
*/
public class CreateTable {private static String addr="HDP233,HDP232,HDP231";
private static String port="2181";
private static Connection connection;/**
* 获取连接
*/
public static void getConnection(){
Configuration conf = HBaseConfiguration.create();conf.set("hbase.zookeeper.quorum",addr);
conf.set("hbase.zookeeper.property.clientPort", port);
try {
connection = ConnectionFactory.createConnection(conf);
} catch (IOException e) {
e.printStackTrace();
}
}/*
* 关闭连接
*/
public static void close() {
/**
* close connection
**/
if (connection != null) {
try {
connection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}public static void main(String[] args) {
createTablePrePartition();
}/**
* 建表
*/
public static void createTable() {
getConnection();
try {
//获取admin实例
Admin admin = connection.getAdmin();
//创建表描述符
HTableDescriptor tableDescriptor = new HTableDescriptor(TableName.valueOf("test_create"));
//添加列族描述符到表描述符中
HColumnDescriptor columnDescriptor = new HColumnDescriptor(Bytes.toBytes("info"));
tableDescriptor.addFamily(columnDescriptor);
//调用create方法
admin.createTable(tableDescriptor);
//检查表是否可用
boolean avail = admin.isTableAvailable(TableName.valueOf("test_create"));
System.out.println("Table available: " + avail);
} catch (IOException e) {
e.printStackTrace();
} finally {
close();
}
}//---------------------------------------通过预分区建表-----------------------------------------
/**
* Printing regions of table: test_pre_partition1
[1]start key: ,end key:1
[2]start key:1 ,end key:13
[3]start key:13 ,end key:25
[4]start key:25 ,end key:37
[5]start key:37 ,end key:49
[6]start key:49 ,end key:61
[7]start key:61 ,end key:73
[8]start key:73 ,end key:85
[9]start key:85 ,end key:100
[10]start key:100 ,end key:
Printing regions of table: test_pre_partition2
[1]start key: ,end key:A
[2]start key:A ,end key:D
[3]start key:D ,end key:G
[4]start key:G ,end key:K
[5]start key:K ,end key:O
[6]start key:O ,end key:T
[7]start key:T ,end key:
*/
/**
* 打印表中region信息
* @param tableName
* @throws IOException
*/
public static void printTableRegions(String tableName) throws IOException {
System.out.println("Printing regions of table: " + tableName);
//返回表中所有region的起始行键与终止行键列表
RegionLocator regionLocator = connection.getRegionLocator(TableName.valueOf(tableName));
//获取所有region的边界。
//第一个region的起始行键与最后一个region的终止行键都是空字节，这是HBase中默认的规则
//起始和终止行键都是已经计算好的，或是提供给用户的拆分键。
//需要注意的是，前一个region的终止行键与后一个region的起始行键是串联起来的
//终止行键不包含在前一个region中，而是作为起始行键包含在后一个region中。
Pair<byte[][], byte[][]> pair = regionLocator.getStartEndKeys();
for(int n = 0; n < pair.getFirst().length; n++) {
byte[] sk = pair.getFirst()[n];
byte[] ek = pair.getSecond()[n];
System.out.println("[" + (n + 1) + "]" +
"start key:" + (sk.length == 8 ? Bytes.toLong(sk) : Bytes.toStringBinary(sk)) +
" ,end key:" + (ek.length == 8 ? Bytes.toLong(ek) : Bytes.toStringBinary(ek)));
}
}
/**
* 通过预分区的方式建表
* @throws IOException
*/
public static void createTablePrePartition() {
getConnection();
String tableName = "test_pre_partition1";
String tableName2 = "test_pre_partition2";
try {
//获取admin实例
Admin admin = connection.getAdmin();
//创建表描述符
HTableDescriptor tableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));
//添加列族描述符到表描述符中
HColumnDescriptor columnDescriptor = new HColumnDescriptor(Bytes.toBytes("info"));
tableDescriptor.addFamily(columnDescriptor);
//调用create方法,同时设置region边界。
//能够以特定数量拆分特定起始行键和特定终止行键，并创建表。
//startKey必须小于endKey，并且numRegions需要大于等于3，否则会抛出异常，这样才能确保region有最小的集合
//此方法使用Bytes.split()方法计算region边界，然后将计算得到的边界作为已拆分边界列表，并调用createTable(final HTableDescriptor desc, byte[][] splitKeys)方法
admin.createTable(tableDescriptor, Bytes.toBytes(1L), Bytes.toBytes(100L), 10);
printTableRegions(tableName); //创建表中region的拆分行键
byte[][] regions = new byte[][] {
Bytes.toBytes("A"),
Bytes.toBytes("D"),
Bytes.toBytes("G"),
Bytes.toBytes("K"),
Bytes.toBytes("O"),
Bytes.toBytes("T")
};
tableDescriptor.setName(TableName.valueOf(tableName2));
//使用新表明和region的已拆分键值列表作为参数调用建表命令
//使用已拆分行键的集合：使用了已经拆分好的region边界列表，因此结果都是与预期相符的。
admin.createTable(tableDescriptor, regions);
printTableRegions(tableName2);
} catch (IOException e) {
e.printStackTrace();
} finally {
close();
}
}
}