第6章 HBase API操作（一）

上篇：第5章 HBase原理

---

1、判断是否有旧的API

操作步骤
（1）打开IDEA工具，创建HBase工程项目步骤：



新建项目后在pom.xml中添加依赖：

<dependencies>
    <dependency>
        <groupId>org.apache.hbase</groupId>
        <artifactId>hbase-server</artifactId>
        <version>1.3.1</version>
    </dependency>

    <dependency>
        <groupId>org.apache.hbase</groupId>
        <artifactId>hbase-client</artifactId>
        <version>1.3.1</version>
    </dependency>

//注意:这个包不用导入，导入的话可能会出错
<dependency>
	<groupId>jdk.tools</groupId>
	<artifactId>jdk.tools</artifactId>
	<version>1.8</version>
	<scope>system</scope>
	<systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>

</dependencies>

（2）在java文件目录下创建一个com.study包，并在该包下创建一个TestHBase类

具体代码的实现：

TestHBase.java

package com.study;

import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HBaseAdmin;

import java.io.IOException;

public class TestHBase {

    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
        HBaseConfiguration configuration = new HBaseConfiguration();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        //获取HBase管理员对象
        HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
        boolean tableExists = admin.tableExists(tableName);

        //关闭资源
        admin.close();

        return tableExists;
    }

    public static void main(String[] args) throws IOException {
        System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));
    }
}

之后，在Linux环境下启动HRegionServer服务

[root@hadoop106 hbase-1.3.1]# jps
7568 DataNode
7508 QuorumPeerMain
8235 HRegionServer
12861 Jps

接着，在IDEA开发工具，运行此程序，控制台打印出：

---

2、判断是否有新的API

首先在HBaseAdmin代码点击查看源码：ctrl+鼠标
说明，需要创建一个Connection来代替Admin，就是新 代替旧的

敲出这个代码 ConnectionFactory，点击（ctrl+鼠标）进去

若HBaseConfiguration对象还是过时，我们可以查看源代码点击进去


HBaseConfiguration#create() to construct a plain Configuration：表示不要重新new HBaseConfiguration

具体代码实现：（过时的API变成新的API）

package com.study;

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.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.HBaseAdmin;

import java.io.IOException;

public class TestHBase {



    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
       // HBaseConfiguration configuration = new HBaseConfiguration();
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        Connection connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();

        //获取HBase管理员对象
      //  HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
     //   boolean tableExists = admin.tableExists(tableName);
        boolean tableExists = admin.tableExists(TableName.valueOf(tableName));

        //关闭资源
        admin.close();

        return tableExists;
    }

    public static void main(String[] args) throws IOException {
        System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));
    }
}

同理：运行此程序，控制台打印出：

代码也可以另一种写法：

package com.study;

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.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import java.io.IOException;

public class TestHBase {
 private   static   Admin admin=null;
static {
    Configuration configuration = HBaseConfiguration.create();
    configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

    Connection connection = null;
    try {
        connection = ConnectionFactory.createConnection(configuration);
        admin = connection.getAdmin();
    } catch (IOException e) {
        e.printStackTrace();
    }


}

  private void close(Connection conn,Admin admin) throws IOException {
     if(conn!=null) {
       conn.close();
     }
     if(admin!=null){
         admin.close();
     }
  }


    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
       // HBaseConfiguration configuration = new HBaseConfiguration();
       /* Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        Connection connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();*/

        //获取HBase管理员对象
      //  HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
     //   boolean tableExists = admin.tableExists(tableName);
        boolean tableExists = admin.tableExists(TableName.valueOf(tableName));

        //关闭资源
        admin.close();

        return tableExists;
    }

    public static void main(String[] args) throws IOException {
        System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));
    }
}

理：运行此程序，控制台打印出：

---

3、HBase创建表

具体代码实现：

package com.study;

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 java.io.IOException;

public class TestHBase {
 private   static   Admin admin=null;
    private static Object String;

    static {
    Configuration configuration = HBaseConfiguration.create();
    configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

    Connection connection = null;
    try {
        connection = ConnectionFactory.createConnection(configuration);
        admin = connection.getAdmin();
    } catch (IOException e) {
        e.printStackTrace();
    }


}


    private void close(Connection conn,Admin admin) throws IOException {
     if(conn!=null) {
       conn.close();
     }
     if(admin!=null){
         admin.close();
     }
  }


    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
        // HBaseConfiguration configuration = new HBaseConfiguration();
       /* Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        Connection connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();*/

        //获取HBase管理员对象
        //  HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
        //   boolean tableExists = admin.tableExists(tableName);
        boolean tableExists = admin.tableExists(TableName.valueOf(tableName));

        //关闭资源
        admin.close();

        return tableExists;

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

            if (tableExist(tableName)) {
                System.out.println("表已存在！！");
                return;
            }
          //创建表描述器
            HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));

            //添加列族
            for (String cf:cfs) {
                //创建列描述器
                HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf);
                //改变列族版本
               // hColumnDescriptor.setMaxVersions(1);默认是1个

                hTableDescriptor.addFamily(hColumnDescriptor);
            }

            //创建表操作
            admin.createTable(hTableDescriptor);

            System.out.println("表创建成功！！");
        }


    public static void main(String[] args) throws IOException {
        System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));

     createTable("staff","info");
        System.out.println(tableExist("staff"));
    }
}

运行此程序，控制台打印出：

这样我们就可以在Linux环境下，在Hbase的客户端查看表中的数据：

hbase(main):008:0> list
TABLE                                                                                                                                                                      
staff                                                                                                                                                                      
1 row(s) in 2.0910 seconds

=> ["staff"]

说明：staff表被创建成功！

---

4、HBase删除表

具体带代码实现：

package com.study;

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 java.io.IOException;

public class TestHBase {
   private   static   Admin admin=null;
   private static Connection connection = null;

    static {
    Configuration configuration = HBaseConfiguration.create();
    configuration.set("hbase.zookeeper.quorum", "192.168.219.105");


    try {
        connection = ConnectionFactory.createConnection(configuration);
        admin = connection.getAdmin();
    } catch (IOException e) {
        e.printStackTrace();
    }


}


    private static void close(Connection conn,Admin admin) throws IOException {
     if(conn!=null) {
       conn.close();
     }
     if(admin!=null){
         admin.close();
     }
  }


    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
        // HBaseConfiguration configuration = new HBaseConfiguration();
       /* Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        Connection connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();*/

        //获取HBase管理员对象
        //  HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
        //   boolean tableExists = admin.tableExists(tableName);
        boolean tableExists = admin.tableExists(TableName.valueOf(tableName));

        //关闭资源
        admin.close();

        return tableExists;

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

            if (tableExist(tableName)) {
                System.out.println("表已存在！！");
                return;
            }
          //创建表描述器
            HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));

            //添加列族
            for (String cf:cfs) {
                //创建列描述器
                HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf);
                //改变列族版本
               // hColumnDescriptor.setMaxVersions(1);默认是1个

                hTableDescriptor.addFamily(hColumnDescriptor);
            }

            //创建表操作
            admin.createTable(hTableDescriptor);

            System.out.println("表创建成功！！");
        }

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

        //使用不可用（下线）
            admin.disableTable(TableName.valueOf(tableName));

            //执行删除操作
            admin.deleteTable(TableName.valueOf(tableName));

            System.out.println("表已删除！！");


        }

    public static void main(String[] args) throws IOException {
   //     System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));

        //创建表测试
  //   createTable("staff","info");


        //删除表测试
        deleteTable("staff");
        System.out.println(tableExist("staff"));
        //关闭资源
        close(connection,admin);

    }
}

运行此程序，控制台打印出：

这样我们就可以在Linux环境下，在Hbase的客户端查看表中的数据：

hbase(main):009:0> list
TABLE                                                                                                                                                                      
0 row(s) in 0.1240 seconds

=> []

说明：staff表被删除成功！

若对不存在的表进行删除，程序会报错

解决这个问题，我们需要对程序进行作一个判断：

 if(!tableExist(tableName)){
               return;
           }

具体代码（全部）

package com.study;

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 java.io.IOException;

public class TestHBase {
   private   static   Admin admin=null;
   private static Connection connection = null;

    static {
    Configuration configuration = HBaseConfiguration.create();
    configuration.set("hbase.zookeeper.quorum", "192.168.219.105");


    try {
        connection = ConnectionFactory.createConnection(configuration);
        admin = connection.getAdmin();
    } catch (IOException e) {
        e.printStackTrace();
    }


}


    private static void close(Connection conn,Admin admin) throws IOException {
     if(conn!=null) {
       conn.close();
     }
     if(admin!=null){
         admin.close();
     }
  }


    //判断表是否存在
    public  static boolean tableExist(String tableName) throws IOException {
        //HBase配置文件
        // HBaseConfiguration configuration = new HBaseConfiguration();
       /* Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum", "192.168.219.105");

        Connection connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();*/

        //获取HBase管理员对象
        //  HBaseAdmin admin = new HBaseAdmin(configuration);

        //执行
        //   boolean tableExists = admin.tableExists(tableName);
        boolean tableExists = admin.tableExists(TableName.valueOf(tableName));

        //关闭资源
        admin.close();

        return tableExists;

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

            if (tableExist(tableName)) {
                System.out.println("表已存在！！");
                return;
            }
          //创建表描述器
            HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));

            //添加列族
            for (String cf:cfs) {
                //创建列描述器
                HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf);
                //改变列族版本
               // hColumnDescriptor.setMaxVersions(1);默认是1个

                hTableDescriptor.addFamily(hColumnDescriptor);
            }

            //创建表操作
            admin.createTable(hTableDescriptor);

            System.out.println("表创建成功！！");
        }

        //删除表
        public static void deleteTable(String tableName) throws IOException {
           if(!tableExist(tableName)){
               return;
           }

        //使用不可用（下线）
            admin.disableTable(TableName.valueOf(tableName));

            //执行删除操作
            admin.deleteTable(TableName.valueOf(tableName));

            System.out.println("表已删除！！");


        }

    public static void main(String[] args) throws IOException {
   //     System.out.println( tableExist("student"));
        System.out.println(tableExist("staff"));

        //创建表测试
  //   createTable("staff","info");


        //删除表测试
        deleteTable("staff");
        System.out.println(tableExist("staff"));
        //关闭资源
        close(connection,admin);

    }
}

重新启动程序运行，控制台打印信息：

做了逻辑判断后，尽管数据没有表，进行删除也不会报错！

注意：
HBase的API操作跟别的API操作有点不同：
（1）别的API操作没有数据，删除不存在的数据是不会报错的！
（2）HBase的API在做项目的过程中，删除不存在的数据会报错，所以，在测试删除不存在的数据，必要做逻辑判断：

if(!tableExist(tableName)){
               return;
           }