一、实验目的

熟悉HBase数据库操作常用的Java API

二、实验平台

  1. 操作系统：CentOS 8
  2. Hadoop版本：3.2.3
  3. HBase版本：2.4.12
  4. jdk版本：1.8
  5. Java IDE：eclipse

三、实验过程

1. 创建表

  1. 创建项目
    在eclipse中创建项目，首先将先前下载的压缩包”hbase-2.4.12-tar.bin.gz"解压,然后将其目录下的lib目录下的所有jar包拷贝到项目的lib目录下,然后build to path,最后就可以编写代码了
    在这里插入图片描述
  2. 创建表
    在HBase种创建dept和emp表，列都为data
    import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.util.Bytes;

public class Task{
	
	public void createTable()throws Exception{
		//获得Configuration对象
		Configuration config=HBaseConfiguration.create();
		//连接hbase
		Connection connection=ConnectionFactory.createConnection(config);
		//获取admin对象
		Admin admin=connection.getAdmin();
		//定义表名
		TableName tableName1=TableName.valueOf("dept");
		TableName tableName2=TableName.valueOf("emp");
		//定义表对象
		//HTableDescriptor htd=new HTableDescriptor(tableName);
		TableDescriptorBuilder tableDescriptor1 = TableDescriptorBuilder.newBuilder(tableName1); 
		TableDescriptorBuilder tableDescriptor2 = TableDescriptorBuilder.newBuilder(tableName2); 
		//定义列族对象
		//HColumnDescriptor hcd=new HColumnDescriptor("data");
		ColumnFamilyDescriptor family = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("data")).build();
		//添加
		// htd.addFamily(hcd);
		tableDescriptor1.setColumnFamily(family);
		tableDescriptor2.setColumnFamily(family);
		//创建表
		admin.createTable(tableDescriptor1.build());
		admin.createTable(tableDescriptor2.build());
	}
}

2. 添加数据

在HBase中创建表tb_step2,列簇都为data，添加数据：

  • 行号分别为：row1，row2；
  • 列名分别为：1，2；
  • 值分别为：张三丰，张无忌。
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.util.Bytes;

public class Tesk {

	public void insertInfo()throws Exception{
		//获得Configuration对象
		Configuration config=HBaseConfiguration.create();
		//连接hbase
		Connection connection=ConnectionFactory.createConnection(config);
		//获取admin对象
		Admin admin=connection.getAdmin();
		//定义表名
		TableName tableName=TableName.valueOf("tb_step2");
		//定义表对象
		TableDescriptorBuilder tableDescriptor = TableDescriptorBuilder.newBuilder(tableName); 
		//定义列族对象
		ColumnFamilyDescriptor family = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("data")).build();
		//添加
		tableDescriptor.setColumnFamily(family);
		//创建表
		admin.createTable(tableDescriptor.build());
		Table table = connection.getTable(tableName);//获取Table对象  
		try {  
			Put put1 = new Put(Bytes.toBytes("row1"));
			put1.addColumn(Bytes.toBytes("data"),Bytes.toBytes(String.valueOf(1)),Bytes.toBytes("张三丰"));
			Put put2 = new Put(Bytes.toBytes("row2"));
		put2.addColumn(Bytes.toBytes("data"),Bytes.toBytes(String.valueOf(2)),Bytes.toBytes("张无忌"));
			table.put(put1);
			table.put(put2);        //向表中添加数据
		} finally {  
			//使用完了要释放资源  
			table.close();  
		}  
	}
}

3. 获取数据

输出t_step3表中行号为row1，列族为data:1的值（以utf-8编码），输出table_step3表中所有行的行名称

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.util.Bytes;

public class Tesk {
	
	public void queryTableInfo()throws Exception{
		//获得Configuration对象
		Configuration config=HBaseConfiguration.create();
		//连接hbase
		Connection connection=ConnectionFactory.createConnection(config);
		//创建表
		TableName tableName3 = TableName.valueOf("t_step3");
		Table table3 = connection.getTable(tableName3);//获取Table对象
		//获取数据
		Get get=new Get(Bytes.toBytes("row1"));
		//通过table对象获取数据
		Result result = table3.get(get); 
		byte[] valueBytes = result.getValue(Bytes.toBytes("data"), Bytes.toBytes("1")); //获取到的是字节数组  
		//将字节转成字符串  
		String valueStr = new String(valueBytes,"utf-8");  
		System.out.println("value:" + valueStr);
		TableName tableName3_1 = TableName.valueOf("table_step3");
		Table table3_1 = connection.getTable(tableName3_1);//获取Table对象
		Scan scan = new Scan();  
		ResultScanner scanner = table3_1.getScanner(scan);  
		try {  
			for (Result scannerResult: scanner) {  
				//System.out.println("Scan: " + scannerResult);  
				byte[] row = scannerResult.getRow();  
				System.out.println("rowName:" + new String(row,"utf-8"));  
			}  
		} finally {  
			scanner.close();  
		}  
		
	}
}

4. 删除表

删除t_step4表

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.util.Bytes;

public class Tesk {
	
	public void deleteTable()throws Exception{
		//获得Configuration对象
		Configuration config=HBaseConfiguration.create();
		//连接hbase
		Connection connection=ConnectionFactory.createConnection(config);
		//获取admin对象
		Admin admin=connection.getAdmin();
		TableName tableName=TableName.valueOf("t_step4");
		admin.disableTable(tableName);
		admin.deleteTable(tableName);
		
	}
}
# hbase # java # hadoop
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