图文详解：内存总是不够，我靠HBase说服了Leader

Configuration configuration = HBaseConfiguration.create();
configuration.set("hbase.zookeeper.quorum", "XXXX.XXX.XXX");
configuration.set("hbase.zookeeper.property.clientPort", "2181");
configuration.set("zookeeper.znode.parent", "XXXXX");
Connection connection = ConnectionFactory.createConnection(configuration);

tar -zxvf hbase-0.98.6-hadoop2-bin.tar.gz

export JAVA_HOME=/opt/modules/jdk1.7.0_79

<configuration>
 <property>
    <name>hbase.rootdir</name>
    <value>hdfs://hadoop-senior.shinelon.com:8020/hbase</value>
  </property>
  <property>
    <name>hbase.cluster.distributed</name>
    <value>true</value>
  </property>
  <property>
    <name>hbase.zookeeper.quorum</name>
    <value>hadoop-senior.shinelon.com</value>
  </property>
</configuration>

package com.initialize;
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 org.apache.hadoop.hbase.regionserver.BloomType;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
/**
 *  
 *  1、构建连接
 *  2、从连接中取到一个表DDL操作工具admin
 *  3、admin.createTable(表描述对象);
 *  4、admin.disableTable(表名);
 * 5、admin.deleteTable(表名);
 * 6、admin.modifyTable(表名，表描述对象); 
 *
 */
public class HbaseClientDemo {

    Connection conn = null;

    @Before
    public void getConn() throws IOException {
        //构建一个连接对象
        Configuration conf = HBaseConfiguration.create();//会自动加载hbase-site.xml
        conf.set("hbase.zookeeper.quorum","n1:2181,n2:2181,n3:2181");

        conn = ConnectionFactory.createConnection(conf);
    }

    /**
     * DDL
     * 创建表
     */
    @Test
    public void testCreateTable() throws  Exception{

        //从连接中构造一个DDL操作器
        Admin admin = conn.getAdmin();

        //创建一个标定义描述对象
        HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf("user_info"));

        //创建列族定义描述对象
        HColumnDescriptor hColumnDescriptor_1 = new HColumnDescriptor("base_info");
        hColumnDescriptor_1.setMaxVersions(3);

        HColumnDescriptor hColumnDescriptor_2 = new HColumnDescriptor("extra_info");

        //将列族定义信息对象放入表定义对象中
        hTableDescriptor.addFamily(hColumnDescriptor_1);
        hTableDescriptor.addFamily(hColumnDescriptor_2);

        //用ddl操作器对象：admin来创建表
        admin.createTable(hTableDescriptor);

        //关闭连接
        admin.close();
        conn.close();

    }

    /**
     * 删除表
     */
    @Test
    public void testDropTable() throws  Exception{

        Admin admin = conn.getAdmin();

        //停用表
        admin.disableTable(TableName.valueOf("user_info"));
        //删除表
        admin.deleteTable(TableName.valueOf("user_info"));

        admin.close();
        conn.close();
    }

    /**
     * 修改表定义--添加一个列族
     */
    @Test
    public void testAlterTable() throws  Exception{

        Admin admin = conn.getAdmin();

        //取出旧的表定义信息
        HTableDescriptor tableDescriptor = admin.getTableDescriptor(TableName.valueOf("user_info"));

        //新构造一个列族定义
        HColumnDescriptor hColumnDescriptor = new HColumnDescriptor("other_info");
        hColumnDescriptor.setBloomFilterType(BloomType.ROWCOL);//设置该列族的布隆过滤器类型

        //将列族定义添加到表定义对象中
        tableDescriptor.addFamily(hColumnDescriptor);

        //将修改过的表定义交给admin去提交
        admin.modifyTable(TableName.valueOf("user_info"), tableDescriptor);

        admin.close();
        conn.close();
    }
}

package com.initialize;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellScanner;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;

public class HbaseClientDML {

    Connection conn = null;

    @Before
    public void getConn() throws IOException {
        //构建一个连接对象
        Configuration conf = HBaseConfiguration.create();//会自动加载hbase-site.xml
        conf.set("hbase.zookeeper.quorum","n1:2181,n2:2181,n3:2181");

        conn = ConnectionFactory.createConnection(conf);
    }


    /**
     * 增，改：put来覆盖
     */
    @Test
    public void testPut() throws  Exception{

        //获取一个操作指定表的table对象，进行DML操作
        Table table = conn.getTable(TableName.valueOf("user_info"));

        //构造要插入的数据为一个Put类型（一个put对象只能对应一个rowkey)的对象
        Put put = new Put(Bytes.toBytes("001"));
        put.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("username"),Bytes.toBytes("小羽"));
        put.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("age"), Bytes.toBytes("18"));
        put.addColumn(Bytes.toBytes("extra_info"), Bytes.toBytes("addr"), Bytes.toBytes("成都"));

        Put put2 = new Put(Bytes.toBytes("002"));
        put2.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("username"), Bytes.toBytes("小娜"));
        put2.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("age"), Bytes.toBytes("17"));
        put2.addColumn(Bytes.toBytes("extra_info"), Bytes.toBytes("addr"), Bytes.toBytes("成都"));

        ArrayList<Put> puts = new ArrayList<>();
        puts.add(put);
        puts.add(put2);

        //***去
        table.put(puts);

        table.close();
        conn.close();
    }

    /***
     * 循环插入大量数据
     */
    @Test
    public void testManyPuts() throws Exception{

        Table table = conn.getTable(TableName.valueOf("user_info"));
        ArrayList<Put> puts = new ArrayList<>();

        for(int i=0;i<10000;i++){
            Put put = new Put(Bytes.toBytes(""+i));
            put.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("usernaem"), Bytes.toBytes("小羽" +i));
            put.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("age"), Bytes.toBytes((18+i) + ""));
            put.addColumn(Bytes.toBytes("extra_info"), Bytes.toBytes("addr"), Bytes.toBytes("成都"));

            puts.add(put);
        }

        table.put(puts);
    }

    /**
     * 删
     */
    @Test
    public void testDelete() throws Exception{
        Table table = conn.getTable(TableName.valueOf("user_info"));

        //构造一个对象封装要删除的数据信息
        Delete delete1 = new Delete(Bytes.toBytes("001"));

        Delete delete2 = new Delete(Bytes.toBytes("002"));
        delete2.addColumn(Bytes.toBytes("extra_info"), Bytes.toBytes("addr"));

        ArrayList<Delete> dels = new ArrayList<>();
        dels.add(delete1);
        dels.add(delete2);

        table.delete(dels);

        table.close();
        conn.close();
    }

    /**
     * 查
     */
    @Test
    public void  testGet() throws Exception{

        Table table = conn.getTable(TableName.valueOf("user_info"));

        Get get = new Get("002".getBytes());

        Result result = table.get(get);

        //从结果中取用户指定的某个key和value的值
        byte[] value = result.getValue("base_info".getBytes(), "age".getBytes());
        System.out.println(new String(value));

        System.out.println("======================");

        //遍历整行结果中的所有kv单元格
        CellScanner cellScanner = result.cellScanner();
        while(cellScanner.advance()){
            Cell cell = cellScanner.current();

            byte[] rowArray = cell.getRowArray();//本kv所属行键的字节数组
            byte[] familyArray = cell.getFamilyArray();//列族名的字节数组
            byte[] qualifierArray = cell.getQualifierArray();//列名的字节数组
            byte[] valueArray = cell.getValueArray();//value字节数组
            
            System.out.println("行键：" + new String(rowArray, cell.getRowOffset(), cell.getRowLength()));
            System.out.println("列族名：" + new String(familyArray, cell.getFamilyOffset(), cell.getFamilyLength()));
            System.out.println("列名：" + new String(qualifierArray, cell.getQualifierOffset(), cell.getQualifierLength()));
            System.out.println("value：" + new String(valueArray, cell.getValueOffset(), cell.getValueLength()));

        }
        table.close();
        conn.close();

    }


    /**
     * 按行键范围查询数据
     */
    @Test
    public void testScan() throws Exception{

        Table table = conn.getTable(TableName.valueOf("user_info"));

        //包含起始行键，不包含结束行键，但是如果真的是想要查询出末尾的那个行键，可以在尾行键上拼接一个不可见的字符（\000)
        Scan scan = new Scan("10".getBytes(), "10000\001".getBytes());

        ResultScanner scanner =table.getScanner(scan);

        Iterator<Result> iterator = scanner.iterator();

        while(iterator.hasNext()){

            Result result =iterator.next();
            //遍历整行结果中的所有kv单元格
            CellScanner cellScanner = result.cellScanner();
            while(cellScanner.advance()){
                Cell cell = cellScanner.current();

                byte[] rowArray = cell.getRowArray();//本kv所属行键的字节数组
                byte[] familyArray = cell.getFamilyArray();//列族名的字节数组
                byte[] qualifierArray = cell.getQualifierArray();//列明的字节数组
                byte[] valueArray = cell.getValueArray();//value字节数组

                System.out.println("行键：" + new String(rowArray, cell.getRowOffset(), cell.getRowLength()));
                System.out.println("列族名：" + new String(familyArray, cell.getFamilyOffset(), cell.getFamilyLength()));
                System.out.println("列名：" + new String(qualifierArray, cell.getQualifierOffset(), cell.getQualifierLength()));
                System.out.println("value：" + new String(valueArray, cell.getValueOffset(), cell.getValueLength()));
            }
            System.out.println("----------------------");
        }
    }

    @Test
    public void test(){
        String a = "000";
        String b = "000\0";

        System.out.println(a);
        System.out.println(b);

        byte[] bytes = a.getBytes();
        byte[] bytes2 = b.getBytes();
        
        System.out.println("");
    }
}