hbase学习（一）hbase单机部署和java客户端连接单机hbase

最近看了些hbase的东西，打算写点什么，谁知鼓捣的过程中步步是坑，最终呕心沥血，憋出了这篇文章，实属不易。

hbase和hive总是成对出现的，简单说，hbase是数据库，hive是mapReduce作业。

先从hbase单机部署说起，尽量说的简洁点，说多了都是眼泪。

1.给服务器起个机器名，iptables关掉，同时本地绑定host。

起个机器名

vi /etc/hosts

127.0.0.1 localhost
211.155.225.210 love-kaige

vi /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=love-kaige

关闭iptables

service iptables stop
chkconfig iptables off

本地绑定host
C:\Windows\System32\drivers\etc\hosts
211.155.225.210 love-kaige

然后reboot重启机子，执行
hostname显示love-kaige，service iptables status 显示 iptables: Firewall is not running. 即OK。

2.下载安装jdk和hbase。

jdk应该关系不大，我安装的是jdk-7u51-linux-x64.rpm，环境变量配好即可，此处略过。

hbase下载的是稳定版，地址：http://mirrors.aliyun.com/apache/hbase/stable/hbase-0.94.18.tar.gz。阿里云对apache下的项目和linux不同的发行版都做了镜像，方便了广大的码农，给个赞。

解压hbase，然后对hbase-site.xml进行修改，修改如下：

<configuration>
        <property>
                <name>hbase.rootdir</name>
                <value>file:/root/hbase</value>
        </property>
</configuration>

然后去hbase的bin目录，./start-hbase.sh起起来。

3.编写java代码。

添加依赖：

 <dependency>
	   <groupId> org.apache.hadoop</groupId >
	   <artifactId> hadoop-core </artifactId>
	   <version> 1.0.4</version >
 </dependency>
 <dependency>
	   <groupId> org.apache.hbase</groupId >
	   <artifactId> hbase</artifactId >
	   <version> 0.94.18</version >
 </dependency>

服务端和客户端的版本最好一致，现在都是0.94.18，免得出现莫名奇妙的问题。hadoop的版本和hbase的版本也有对应关系，把官网的hbase和hadoop的版本匹配表搬过来，

Table 2.1. Hadoop version support matrix

S = supported and tested,支持
X = not supported,不支持
NT = not tested enough.可以运行但测试不充分

由于 HBase 依赖 Hadoop，它配套发布了一个Hadoop jar 文件在它的 lib 下。该套装jar仅用于独立模式。在分布式模式下，Hadoop版本必须和HBase下的版本一致。用你运行的分布式Hadoop版本jar文件替换HBase lib目录下的Hadoop jar文件，以避免版本不匹配问题。确认替换了集群中所有HBase下的jar文件。Hadoop版本不匹配问题有不同表现，但看起来都像挂掉了。

贴代码

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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.KeyValue;
import org.apache.hadoop.hbase.MasterNotRunningException;
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.Scan;
import org.apache.hadoop.hbase.util.Bytes;


/**
 * 
 * @author yankai913@gmail.com
 * @date 2014-4-28
 */
public class SimpleClient {

    static final String rowKey = "row1";
    static HBaseAdmin hBaseAdmin;
    static Configuration conf;

    static {
        conf = HBaseConfiguration.create();
        conf.set("hbase.zookeeper.quorum", "love-kaige");
        try {
            hBaseAdmin = new HBaseAdmin(conf);
        }
        catch (MasterNotRunningException e) {
            e.printStackTrace();
        }
        catch (ZooKeeperConnectionException e) {
            e.printStackTrace();
        }
    }


    public static void createTable(String tableName, String[] columns) throws Exception {
        dropTable(tableName);
        HTableDescriptor hTableDescriptor = new HTableDescriptor(tableName);
        for (String columnName : columns) {
            HColumnDescriptor column = new HColumnDescriptor(columnName);
            hTableDescriptor.addFamily(column);
        }
        hBaseAdmin.createTable(hTableDescriptor);
        System.out.println("create table successed");
    }


    public static void dropTable(String tableName) throws Exception {
        if (hBaseAdmin.tableExists(tableName)) {
            hBaseAdmin.disableTable(tableName);
            hBaseAdmin.deleteTable(tableName);
        }
        System.out.println("drop table successed");
    }


    public static HTable getHTable(String tableName) throws Exception {
        return new HTable(conf, tableName);
    }


    public static void insert(String tableName, Map<String, String> map) throws Exception {
        HTable hTable = getHTable(tableName);
        byte[] row1 = Bytes.toBytes(rowKey);
        Put p1 = new Put(row1);
        for (String columnName : map.keySet()) {
            byte[] value = Bytes.toBytes(map.get(columnName));
            String[] str = columnName.split(":");
            byte[] family = Bytes.toBytes(str[0]);
            byte[] qualifier = null;
            if (str.length > 1) {
                qualifier = Bytes.toBytes(str[1]);
            }
            p1.add(family, qualifier, value);
        }
        hTable.put(p1);
        Get g1 = new Get(row1);
        Result result = hTable.get(g1);
        System.out.println("Get: " + result);
        System.out.println("insert successed");
    }


    public static void delete(String tableName, String rowKey) throws Exception {
        HTable hTable = getHTable(tableName);
        List<Delete> list = new ArrayList<Delete>();
        Delete d1 = new Delete(Bytes.toBytes(rowKey));
        list.add(d1);
        hTable.delete(list);
        Get g1 = new Get(Bytes.toBytes(rowKey));
        Result result = hTable.get(g1);
        System.out.println("Get: " + result);
        System.out.println("delete successed");
    }


    public static void selectOne(String tableName, String rowKey) throws Exception {
        HTable hTable = getHTable(tableName);
        Get g1 = new Get(Bytes.toBytes(rowKey));
        Result result = hTable.get(g1);
        foreach(result);
        System.out.println("selectOne end");
    }


    private static void foreach(Result result) throws Exception {
        for (KeyValue keyValue : result.raw()) {
            StringBuilder sb = new StringBuilder();
            sb.append(Bytes.toString(keyValue.getRow())).append("\t");
            sb.append(Bytes.toString(keyValue.getFamily())).append("\t");
            sb.append(Bytes.toString(keyValue.getQualifier())).append("\t");
            sb.append(keyValue.getTimestamp()).append("\t");
            sb.append(Bytes.toString(keyValue.getValue())).append("\t");
            System.out.println(sb.toString());
        }
    }


    public static void selectAll(String tableName) throws Exception {
        HTable hTable = getHTable(tableName);
        Scan scan = new Scan();
        ResultScanner resultScanner = null;
        try {
            resultScanner = hTable.getScanner(scan);
            for (Result result : resultScanner) {
                foreach(result);
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            if (resultScanner != null) {
                resultScanner.close();
            }
        }
        System.out.println("selectAll end");
    }


    public static void main(String[] args) throws Exception {
        String tableName = "tableTest";
        String[] columns = new String[] { "column_A", "column_B" };
        createTable(tableName, columns);
        Map<String, String> map = new HashMap<String, String>();
        map.put("column_A", "AAA");
        map.put("column_B:1", "b1");
        map.put("column_B:2", "b2");
        insert(tableName, map);
        selectOne(tableName, rowKey);
        selectAll(tableName);
        delete(tableName, rowKey);
        dropTable(tableName);
    }

练习代码看这里