3、练习常用的HBase Shell命令+HBase 常用的Java API 及应用实例

目录

• [（一）练习常用的HBase Shell命令](#（一）练习常用的HBase Shell命令)
• • 1、启动HBase
  • 2、练习shell命令
  • • [create scan list describe alter](#create scan list describe alter)
    • put
    • get
    • delete
    • drop
  • 关于NoSQL数据库中的列族和列
  • 3、关闭hbase服务
• [（二）HBase 常用的Java API 及应用实例](#（二）HBase 常用的Java API 及应用实例)
• • 1、启动hbase服务
  • 2、启动eclipse
  • [3、新建java project](#3、新建java project)
  • • 导入jar包
    • 创建类文件
    • [常用Java API:](#常用Java API:)
    • [打开hbase shell](#打开hbase shell)
    • [退出hbase shell ------exit](#退出hbase shell ——exit)
  • [4、关闭 hbase](#4、关闭 hbase)

（一）练习常用的HBase Shell命令

1、启动HBase

先启动HDFS 再启动HBase

进入shell交互式执行环境

2、练习shell命令

create scan list describe alter

put

get

delete

drop

删除表前要disable它

关于NoSQL数据库中的列族和列

这些数据库允许你以非常灵活的方式存储和检索数据

3、关闭hbase服务

（二）HBase 常用的Java API 及应用实例

1、启动hbase服务

2、启动eclipse

3、新建java project

导入jar包

导入/usr/local/hbase/lib中的所有jar包

再导入/usr/local/hbase/lib/client-facing-thirdparty中的所有jar 包

创建类文件

常用Java API:

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;

public class ExampleForHBase {
    public static Configuration configuration;
    public static Connection connection;
    public static Admin admin;

    public static void main(String[] args) throws IOException {
        init();
        createTable("student", new String[]{"score"});
        insertData("student", "zhangsan", "score", "English", "69");
        insertData("student", "zhangsan", "score", "Math", "86");
        insertData("student", "zhangsan", "score", "Computer", "77");
        getData("student", "zhangsan", "score", "English");
        close();
    }

    public static void init() {
        configuration = HBaseConfiguration.create();
        configuration.set("hbase.rootdir", "hdfs://localhost:9000/hbase");
        try {
            connection = ConnectionFactory.createConnection(configuration);
            admin = connection.getAdmin();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void close() {
        try {
            if (admin != null) {
                admin.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void createTable(String myTableName, String[] colFamily) throws IOException {
        TableName tableName = TableName.valueOf(myTableName);
        if (admin.tableExists(tableName)) {
            System.out.println("table is exists!");
        } else {
            TableDescriptorBuilder tableDescriptor = TableDescriptorBuilder.newBuilder(tableName);
            for (String str : colFamily) {
                ColumnFamilyDescriptor family = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(str)).build();
                tableDescriptor.setColumnFamily(family);
            }
            admin.createTable(tableDescriptor.build());
        }
    }

    public static void insertData(String tableName, String rowKey, String colFamily, String col, String val) throws IOException {
        Table table = connection.getTable(TableName.valueOf(tableName));
        Put put = new Put(rowKey.getBytes());
        put.addColumn(Bytes.toBytes(colFamily), Bytes.toBytes(col), Bytes.toBytes(val));
        table.put(put);
        table.close();
    }

    public static void getData(String tableName, String rowKey, String colFamily, String col) throws IOException {
        Table table = connection.getTable(TableName.valueOf(tableName));
        Get get = new Get(rowKey.getBytes());
        get.addColumn(Bytes.toBytes(colFamily), Bytes.toBytes(col));
        Result result = table.get(get);
        System.out.println(new String(result.getValue(Bytes.toBytes(colFamily), Bytes.toBytes(col))));
        table.close();
    }
}

run------>run as application

打开hbase shell

list scan

退出hbase shell ------exit

4、关闭 hbase