HBASE基础（4）：语法(2) API (1) DDL

1 环境准备

新建项目后在pom.xml中添加依赖

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-server</artifactId>
    <version>2.0.5</version>
</dependency>

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-client</artifactId>
    <version>2.0.5</version>
</dependency>

2 DDL

创建HBase_DDL类

2.1 判断表是否存在

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.NamespaceExistException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;

public class HBase_DDL {

    //TODO 判断表是否存在
    public static boolean isTableExist(String tableName) throws IOException {

        //1.创建配置信息并配置
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "hadoop102,hadoop103,hadoop104");

        //2.获取与HBase的连接
        Connection connection = ConnectionFactory.createConnection(configuration);

        //3.获取DDL操作对象
        Admin admin = connection.getAdmin();

        //4.判断表是否存在操作
        boolean exists = admin.tableExists(TableName.valueOf(tableName));

        //5.关闭连接
        admin.close();
        connection.close();

        //6.返回结果
        return exists;
    }

}

2.2 创建表

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.NamespaceExistException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;

public class HBase_DDL {

    //TODO 创建表
    public static void createTable(String tableName, String... cfs) throws IOException {

        //1.判断是否存在列族信息
        if (cfs.length <= 0) {
            System.out.println("请设置列族信息！");
            return;
        }

        //2.判断表是否存在
        if (isTableExist(tableName)) {
            System.out.println("需要创建的表已存在！");
            return;
        }

        //3.创建配置信息并配置
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "hadoop102,hadoop103,hadoop104");

        //4.获取与HBase的连接
        Connection connection = ConnectionFactory.createConnection(configuration);

        //5.获取DDL操作对象
        Admin admin = connection.getAdmin();

        //6.创建表描述器构造器
        TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(TableName.valueOf(tableName));

        //7.循环添加列族信息
        for (String cf : cfs) {
            ColumnFamilyDescriptorBuilder columnFamilyDescriptorBuilder = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(cf));
            tableDescriptorBuilder.setColumnFamily(columnFamilyDescriptorBuilder.build());
        }

        //8.执行创建表的操作
        admin.createTable(tableDescriptorBuilder.build());

        //9.关闭资源
        admin.close();
        connection.close();
    }

}

2.3 删除表

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.NamespaceExistException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;

public class HBase_DDL {

    //TODO 删除表
    public static void dropTable(String tableName) throws IOException {

        //1.判断表是否存在
        if (!isTableExist(tableName)) {
            System.out.println("需要删除的表不存在！");
            return;
        }

        //2.创建配置信息并配置
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "hadoop102,hadoop103,hadoop104");

        //3.获取与HBase的连接
        Connection connection = ConnectionFactory.createConnection(configuration);

        //4.获取DDL操作对象
        Admin admin = connection.getAdmin();

        //5.使表下线
        TableName name = TableName.valueOf(tableName);
        admin.disableTable(name);

        //6.执行删除表操作
        admin.deleteTable(name);

        //7.关闭资源
        admin.close();
        connection.close();
    }

}

2.4 创建命名空间

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.NamespaceExistException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;

public class HBase_DDL {

    //TODO 创建命名空间
    public static void createNameSpace(String ns) throws IOException {

        //1.创建配置信息并配置
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "hadoop102,hadoop103,hadoop104");

        //2.获取与HBase的连接
        Connection connection = ConnectionFactory.createConnection(configuration);

        //3.获取DDL操作对象
        Admin admin = connection.getAdmin();

        //4.创建命名空间描述器
        NamespaceDescriptor namespaceDescriptor = NamespaceDescriptor.create(ns).build();

        //5.执行创建命名空间操作
        try {
            admin.createNamespace(namespaceDescriptor);
        } catch (NamespaceExistException e) {
            System.out.println("命名空间已存在！");
        } catch (Exception e) {
            e.printStackTrace();
        }

        //6.关闭连接
        admin.close();
        connection.close();

    }
}