2018-08-21期 Hbase客户端API操作（数据查询，get方式）

package cn.itcast.bigdata.hbase;

import java.io.IOException;

import java.io.InterruptedIOException;

import java.util.ArrayList;

import java.util.Iterator;

import org.apache.commons.collections.comparators.NullComparator;

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.NamespaceDescriptor;

import org.apache.hadoop.hbase.TableName;

import org.apache.hadoop.hbase.ZooKeeperConnectionException;

import org.apache.hadoop.hbase.client.Delete;

import org.apache.hadoop.hbase.client.Get;

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

import org.apache.hadoop.hbase.client.HTable;

import org.apache.hadoop.hbase.client.Put;

import org.apache.hadoop.hbase.client.Result;

import org.apache.hadoop.hbase.client.ResultScanner;

import org.apache.hadoop.hbase.client.RetriesExhaustedWithDetailsException;

import org.apache.hadoop.hbase.client.Scan;

import org.apache.hadoop.hbase.filter.BinaryComparator;

import org.apache.hadoop.hbase.filter.BinaryPrefixComparator;

import org.apache.hadoop.hbase.filter.ByteArrayComparable;

import org.apache.hadoop.hbase.filter.CompareFilter;

import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;

import org.apache.hadoop.hbase.filter.Filter;

import org.apache.hadoop.hbase.filter.FilterBase;

import org.apache.hadoop.hbase.filter.PrefixFilter;

import org.apache.hadoop.hbase.filter.RegexStringComparator;

import org.apache.hadoop.hbase.filter.RowFilter;

import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;

import org.apache.hadoop.hbase.filter.SubstringComparator;

import org.apache.hadoop.hbase.util.Bytes;

import org.apache.hadoop.io.BinaryComparable;

import org.junit.Before;

import org.junit.Test;

/**

* Hbase客户端操作示例

*

* @author songjq

*

*/

/**

* Hbase客户端操作示例

*

* @author songjq

*

*/

public class HbaseAPIDemo {

// 数据库连接对象

private HBaseAdmin hBaseAdmin = null;

// 表连接对象

private HTable hTable = null;

/**

* 获取Hbase对象连接

*

* @throws MasterNotRunningException

* @throws ZooKeeperConnectionException

* @throws IOException

*/

@Before

public void getHbaseConn() throws MasterNotRunningException, ZooKeeperConnectionException, IOException {

/**

* 通过这种通用的配置对象构造的方法来创建一个配置对象 这种方法会自动加载classpath下的

* core-site.xml,hdfs-site.xml,core-default.xml...等这些hadoop的配置文件

*/

// Configuration hdfsconf = new Configuration();

/**

* HBaseConfiguration.create()则会自动加载classpath下的hadoop下的配置文件 及hbase-site.xml

*/

Configuration conf = HBaseConfiguration.create();

/**

* 这里通过zk集群地址连接hbase集群，只需要把hbase-site.xml中 5ae zk连接地址拷贝过来即可

* /usr/local/apps/hbase-0.96.2-hadoop2/conf/hbase-site.xml

*/

conf.set("hbase.zookeeper.quorum", "hadoop-server01:2181,hadoop-server02:2181,hadoop-server03:2181");

// 构造一个DDL操作的客户端对象hBaseAdmin

hBaseAdmin = new HBaseAdmin(conf);

// 实例化表连接对象

hTable = new HTable(conf, "oadb:t_user_info");

}

/**

* 数据查询，get方式【单行查询】 查询方式比较单一

*

* @throws IOException

*/

@Test

public void getTest() throws IOException {

/*

* 构造查询的行键rowkey

*/

Get get = new Get(Bytes.toBytes("user0000010"));

/*

* 查询该行中一个完整列族Family base_info 不指定就查询所有列族

*/

get.addFamily(Bytes.toBytes("base_info"));

/*

* 执行查询

*/

Result result = hTable.get(get);

/*

* 从结果集中获取对应列族的字段

*

*/

byte[] base_info_userid = result.getValue(Bytes.toBytes("base_info"), Bytes.toBytes("userid"));

byte[] base_info_username = result.getValue(Bytes.toBytes("base_info"), Bytes.toBytes("username"));

byte[] base_info_address = result.getValue(Bytes.toBytes("base_info"), Bytes.toBytes("address"));

/*

* 输出结果集 由于hbase是按bytes方式存放数据，因此获取数据字段值时需要和put方式保持一致

*/

System.out.println("base_info_userid:" + Bytes.toString(base_info_userid));

System.out.println("base_info_username:" + Bytes.toString(base_info_username));

System.out.println("base_info_address:" + Bytes.toString(base_info_address));

/*

* 关闭连接

*/

hTable.close();

}

/**

* 数据查询，get方式【多行查询】 查询方式比较单一

*

* @throws IOException

*/

@Test

public void getMoreLines() throws IOException {

/*

* 构造查询list对象

*/

ArrayList<Get> gets = new ArrayList<Get>();

/*

* 循环获取3个get对象

*/

for (int i = 7; i < 10; i++) {

Get get = new Get(Bytes.toBytes("user00000" + i));

/*

* 查询该行键中多个列族中部分字段 family->base_info-> userid,age family->extra_info->orgname

* 不指定就查询所有列族

*/

get.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("userid"));

get.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("age"));

get.addColumn(Bytes.toBytes("extra_info"), Bytes.toBytes("orgname"));

/*

* 将对象get添加到gets

*/

gets.add(get);

}

/*

* 执行多行查询，返回结果集合Result数组

*/

Result[] results = hTable.get(gets);

/*

* 遍历每个数组值

*/

System.out.println("base_info_userid\t" + "base_info_age\t" + "base_info_orgname");

for (Result result : results) {

byte[] base_info_userid = result.getValue(Bytes.toBytes("base_info"), Bytes.toBytes("userid"));

byte[] base_info_age = result.getValue(Bytes.toBytes("base_info"), Bytes.toBytes("age"));

byte[] base_info_orgname = result.getValue(Bytes.toBytes("extra_info"), Bytes.toBytes("orgname"));

System.out.println(Bytes.toString(base_info_userid) + "\t\t\t" + Bytes.toString(base_info_age) + "\t"

+ Bytes.toString(base_info_orgname));

}

/*

* 关闭客户端连接

*/

hTable.close();

}

}