HBase示例

本文概述

• 用例
• Jar文件
• 程式码

让我们看一个HBase示例, 该示例在HBase表中导入文件数据。

用例

我们必须通过Java API将文件中存在的数据导入到HBase表中。

Data_file.txt包含以下数据

1, India, Bihar, Champaran, 2009, April, P1, 1, 5
2, India, Bihar, Patna, 2009, May, P1, 2, 10
3, India, Bihar, Bhagalpur, 2010, June, P2, 3, 15
4, United States, California, Fresno, 2009, April, P2, 2, 5
5, United States, California, Long Beach, 2010, July, P2, 4, 10
6, United States, California, San Francisco, 2011, August, P1, 6, 20

Java代码如下所示

此数据必须输入到要通过JAVA API创建的新HBase表中。必须创建以下列族

"sample, region, time.product, sale, profit".

列族区域具有三个列限定符：国家, 州, 城市

列族时间有两个列限定符：年, 月

Jar文件

确保编写HBase所需的代码时存在以下jar。

1. commons-loging-1.0.4
2. commons-loging-api-1.0.4
3. hadoop-core-0.20.2-cdh3u2
4. hbase-0.90.4-cdh3u2
5. log4j-1.2.15
6. zookeper-3.3.3-cdh3u0

程式码

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.StringTokenizer;

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.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.util.Bytes;


public class readFromFile {
	public static void main(String[] args) throws IOException{
		if(args.length==1)
			{
			Configuration conf = HBaseConfiguration.create(new Configuration());
			HBaseAdmin hba = new HBaseAdmin(conf);
			if(!hba.tableExists(args[0])){
				HTableDescriptor ht = new HTableDescriptor(args[0]);
				ht.addFamily(new HColumnDescriptor("sample"));
				ht.addFamily(new HColumnDescriptor("region"));
				ht.addFamily(new HColumnDescriptor("time"));
				ht.addFamily(new HColumnDescriptor("product"));
				ht.addFamily(new HColumnDescriptor("sale"));
				ht.addFamily(new HColumnDescriptor("profit"));
				hba.createTable(ht);
				System.out.println("New Table Created");
				
				HTable table = new HTable(conf, args[0]);
			
				File f = new File("/home/training/Desktop/data");
				BufferedReader br = new BufferedReader(new FileReader(f));
				String line = br.readLine();
				int i =1;
				String rowname="row";
				while(line!=null && line.length()!=0){
					System.out.println("Ok till here");
					StringTokenizer tokens = new StringTokenizer(line, ", ");
					rowname = "row"+i;
					Put p = new Put(Bytes.toBytes(rowname));
					p.add(Bytes.toBytes("sample"), Bytes.toBytes("sampleNo."), Bytes.toBytes(Integer.parseInt(tokens.nextToken())));
					p.add(Bytes.toBytes("region"), Bytes.toBytes("country"), Bytes.toBytes(tokens.nextToken()));
					p.add(Bytes.toBytes("region"), Bytes.toBytes("state"), Bytes.toBytes(tokens.nextToken()));
					p.add(Bytes.toBytes("region"), Bytes.toBytes("city"), Bytes.toBytes(tokens.nextToken()));
					p.add(Bytes.toBytes("time"), Bytes.toBytes("year"), Bytes.toBytes(Integer.parseInt(tokens.nextToken())));
					p.add(Bytes.toBytes("time"), Bytes.toBytes("month"), Bytes.toBytes(tokens.nextToken()));
					p.add(Bytes.toBytes("product"), Bytes.toBytes("productNo."), Bytes.toBytes(tokens.nextToken()));
					p.add(Bytes.toBytes("sale"), Bytes.toBytes("quantity"), Bytes.toBytes(Integer.parseInt(tokens.nextToken())));
					p.add(Bytes.toBytes("profit"), Bytes.toBytes("earnings"), Bytes.toBytes(tokens.nextToken()));
					i++;
					table.put(p);
					line = br.readLine();
				}
					br.close();
					table.close();
				}
			else
				System.out.println("Table Already exists.Please enter another table name");
		}
		else
			System.out.println("Please Enter the table name through command line");		
	}
}