HBase的API以及基本使用

创建表

package com.zyd.api;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.MasterNotRunningException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.ZooKeeperConnectionException;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.junit.Before;
import org.junit.Test;

public class HBaseApi {
  //创建连接的时候比较慢,可以设置一个连接池
  private HBaseAdmin admin = null;
  private HTable table = null;
  private String TABLE_NAME = "hbaseApi";

  //初始化
  @Before
  public void init() throws MasterNotRunningException, ZooKeeperConnectionException, IOException{
    Configuration conf = new Configuration();
    //连接zookeeper,因为zookeeper知道HMaster地址 第一个是在hbase-site.xml文件中
    conf.set("hbase.zookeeper.quorum","note01,note02,note03");
    admin = new HBaseAdmin(conf);

    table = new HTable(conf, TableName.valueOf(TABLE_NAME));

  } 
  @Test
  public void createTable() throws IOException{
    HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(TABLE_NAME));

    //列族
    HColumnDescriptor hColumnDescriptor1 = new HColumnDescriptor("cf1");
    HColumnDescriptor hColumnDescriptor2 = new HColumnDescriptor("cf2");
    //设置最大版本号,默认是1
    hColumnDescriptor1.setMaxVersions(3);
//    设置生命周期 默认单位为秒
//    hColumnDescriptor1.setTimeToLive(0);
    //add 表示可以创建多个
    hTableDescriptor.addFamily(hColumnDescriptor1);
    hTableDescriptor.addFamily(hColumnDescriptor2);

    admin.createTable(hTableDescriptor);
  }
}

结果通过主页http://note03:60010/master-status 访问tables

添加rowkey column value

//添加数据
  @Test
  public void put() throws RetriesExhaustedWithDetailsException, InterruptedIOException{
  //rowkey
  Put put = new Put("1000".getBytes());
  //列族  列名 value
  put.add("cf1".getBytes(),"name".getBytes(), "zs".getBytes());

  put.add("cf1".getBytes(),"age".getBytes(), "18".getBytes());

//  table.put(put);


  Put put2 = new Put("100".getBytes());
  //列族  列名 value
  put2.add("cf1".getBytes(),"name".getBytes(), "zs".getBytes());

  put2.add("cf1".getBytes(),"age".getBytes(), "18".getBytes());


  List<Put> list = new ArrayList<Put>();
  list.add(put);
  list.add(put2);
  //也可以是批量的插入
  table.put(list);
  }

查询

//查询数据
  @Test
  public void get() throws IOException{
    //获取行
    Get get = new Get("100".getBytes());

    Result result = table.get(get);

    byte[] value = result.getValue("cf1".getBytes(), "name".getBytes());

    Cell cell =  result.getColumnLatestCell("cf1".getBytes(),"name".getBytes());
    //可以得到列族名以及其他的信息等
    byte [] cloneFamily = CellUtil.cloneFamily(cell);
    //hbase里面全是字节 自己要知道类型
    String str = new String(value);
    System.out.println(str);

    System.out.println("第二种方式:"+new String(cloneFamily));
    //动态添加列时,获取类名方法和value
    List<Cell> listCells = result.listCells();

    for (Cell cell2 : listCells) {
      System.out.println("列名(column)"+new String(CellUtil.cloneQualifier(cell2))+"  value"
          + ":"+new String(CellUtil.cloneValue(cell2)));
    }
  }

扫描

//扫描
  @Test
  public void scan() throws IOException{
    Scan scan = new Scan();
    ResultScanner scanner = table.getScanner(scan);

    for (Result result : scanner) {
      List<Cell> lisCells = result.listCells();

      for (Cell cell : lisCells) {
        System.out.println("column:"+new String(CellUtil.cloneQualifier(cell))+"  value"
            + new String(CellUtil.cloneValue(cell)));
      }
    }
  }

出现小bug column 打印的是地址值,

解决:new String()括号位置不正确