Hbase 2.2.2 简单API操作

前言

小案例中有创建表、创建命名空间、插入数据、获取数据。

环境准备

maven依赖可根据自己的版本进行调整

<!--        hbase依赖-->

        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-server</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-client</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-auth</artifactId>
            <version>3.1.3</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-common</artifactId>
            <version>2.2.2</version>
        </dependency>

小案例

代码：

package com.hbase;

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 TestHbaseApi {


    public static void main(String[] args) throws IOException {

        Connection conn = getConn();
        Admin admin = conn.getAdmin();
        try {
            NamespaceDescriptor aDefault = admin.getNamespaceDescriptor("default");
        }catch (NamespaceNotFoundException e){
            //没有命名空间，创建命名空间
            admin.createNamespace(NamespaceDescriptor.create("default").build());
        }
        System.out.println("命名空间存在.");

        //判断表是否存在
        TableName tableName = TableName.valueOf("student");
        boolean exists = admin.tableExists(tableName);
        if (exists){
            //获取表对象
            Table table = conn.getTable(tableName);
            //获取数据
            Result result = table.get(new Get(Bytes.toBytes("1001")));

            if (result.isEmpty()){
                //如果没有数据则新增
                Put put = new Put(Bytes.toBytes("1001"));
                String family = "info";
                String qualifier = "name";
                String value = "zhangsan";
                put.addColumn(Bytes.toBytes(family),Bytes.toBytes(qualifier),Bytes.toBytes(value));
                table.put(put);
                System.out.println("数据新增");
            }else {
                //有数据就展示
                Cell[] cells = result.rawCells();
                for (Cell cell : cells) {
                    System.out.println("family:" + Bytes.toString(CellUtil.cloneFamily(cell)));
                    System.out.println("qualifier:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
                    System.out.println("row:" + Bytes.toString(CellUtil.cloneRow(cell)));
                    System.out.println("value:" + Bytes.toString(CellUtil.cloneValue(cell)));

                }
            }


        }else {
            //表不存在

            //表描述建造者
            TableDescriptorBuilder builder = TableDescriptorBuilder.newBuilder(tableName);
            //列族描述建造者
            ColumnFamilyDescriptorBuilder cfdb = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("info"));
            //设置最大版本号
            cfdb.setMaxVersions(3);
            //创建列族描述
            ColumnFamilyDescriptor familyDescriptor = cfdb.build();
            //将列族加入到表描述中
            builder.setColumnFamily(familyDescriptor);
            //创建表描述
            TableDescriptor tableDescriptor = builder.build();
            //创建表
            admin.createTable(tableDescriptor);
            System.out.println("表创建成功");
        }


    }


    public static Connection getConn() throws IOException {
        Configuration conf = HBaseConfiguration.create();
        conf.set("hbase.zookeeper.quorum","hadoop100,hadoop101,hadoop102");
        conf.set("hbase.zookeeper.property.clientPort", "2181");
        Connection connection = ConnectionFactory.createConnection(conf);
        return connection;
    }


}