文章內(nèi)容

HBase Java客戶端編程

發(fā)布時間: 2012/9/5 16:53:36

本文以Hbase-0.92.0為例，介紹如何在Windows系統(tǒng)，Eclipse IDE集成環(huán)境下，使用Java語言，進行HBase客戶端編程，包含建立表、刪除表、插入記錄、刪除記錄、各種方式下的查詢操作等。

1. 準備工作

1、下載后安裝jdk包;

2、下載eclipse，解壓到本地;

3、下載HBase包，解壓安裝包到本地（這里使用的是 Hbase-0.92.0）。-

2. 搭建開發(fā)環(huán)境

1、運行Eclipse，創(chuàng)建一個新的Java工程“HBaseClient”，右鍵項目根目錄，選擇 “Properties”->“Java Build Path”->“Library”->“Add External JARs”，將HBase解壓后根目錄下的hbase-0.92.0.jar、hbase-0.92.0-tests.jar和lib子目錄下所有jar 包添加到本工程的Classpath下。

2、按照步驟1中的操作，將自己所連接的HBase的配置文件hbase-site.xml添加到本工程的Classpath中，如下所示為配置文件的一個示例：

<configuration>
<property>
<name>hbase.rootdir</name>
<value>hdfs://Hadoop-1:9000/hbase</value>
</property>
<property>
<name>hbase.cluster.distributed</name>
<value>true</value>
</property>
<property>
<name>hbase.zookeeper.quorum</name>
<value>Hadoop-1,hadoop-2,hadoop-3,hadoop-4</value>
</property>
<property>
<name>zookeeper.session.timeout</name>
<value>60000</value>
</property>
<property>
<name>hbase.master</name>
<value>Hadoop-1:60000</value>
</property>
<property>
<name>hbase.zookeeper.property.clientPort</name>
<value>21818</value>
</property>
</configuration>
3、下面可以在Eclipse環(huán)境下進行HBase編程了。

3. HBase基本操作代碼示例

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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.Result;
import org.apache.Hadoop.hbase.client.ResultScanner;
import org.apache.Hadoop.hbase.client.Scan;
import org.apache.Hadoop.hbase.client.Put;
import org.apache.Hadoop.hbase.util.Bytes;

public class HBaseTest {

    private static Configuration conf =null;
     /**
      * 初始化配置
     */
     static {
         conf = HBaseConfiguration.create();
     }

    /**
     * 創(chuàng)建一張表
     */
    public static void creatTable(String tableName, String[] familys) throws Exception {
        HBaseAdmin admin = new HBaseAdmin(conf);
        if (admin.tableExists(tableName)) {
            System.out.println("table already exists!");
        } else {
            HTableDescriptor tableDesc = new HTableDescriptor(tableName);
            for(int i=0; i<familys.length; i++){
                tableDesc.addFamily(new HColumnDescriptor(familys[i]));
            }
            admin.createTable(tableDesc);
            System.out.println("create table " + tableName + " ok.");
        }
    }

    /**
     * 刪除表
     */
    public static void deleteTable(String tableName) throws Exception {
       try {
           HBaseAdmin admin = new HBaseAdmin(conf);
           admin.disableTable(tableName);
           admin.deleteTable(tableName);
           System.out.println("delete table " + tableName + " ok.");
       } catch (MasterNotRunningException e) {
           e.printStackTrace();
       } catch (ZooKeeperConnectionException e) {
           e.printStackTrace();
       }
    }

    /**
     * 插入一行記錄
     */
    public static void addRecord (String tableName, String rowKey, String family, String qualifier, String value)
            throws Exception{
        try {
            HTable table = new HTable(conf, tableName);
            Put put = new Put(Bytes.toBytes(rowKey));
            put.add(Bytes.toBytes(family),Bytes.toBytes(qualifier),Bytes.toBytes(value));
            table.put(put);
            System.out.println("insert recored " + rowKey + " to table " + tableName +" ok.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 刪除一行記錄
     */
    public static void delRecord (String tableName, String rowKey) throws IOException{
        HTable table = new HTable(conf, tableName);
        List list = new ArrayList();
        Delete del = new Delete(rowKey.getBytes());
        list.add(del);
        table.delete(list);
        System.out.println("del recored " + rowKey + " ok.");
    }

    /**
     * 查找一行記錄
     */
    public static void getOneRecord (String tableName, String rowKey) throws IOException{
        HTable table = new HTable(conf, tableName);
        Get get = new Get(rowKey.getBytes());
        Result rs = table.get(get);
        for(KeyValue kv : rs.raw()){
            System.out.print(new String(kv.getRow()) + " " );
            System.out.print(new String(kv.getFamily()) + ":" );
            System.out.print(new String(kv.getQualifier()) + " " );
            System.out.print(kv.getTimestamp() + " " );
            System.out.println(new String(kv.getValue()));
        }
    }

    /**
     * 顯示所有數(shù)據(jù)
     */
    public static void getAllRecord (String tableName) {
        try{
             HTable table = new HTable(conf, tableName);
             Scan s = new Scan();
             ResultScanner ss = table.getScanner(s);
             for(Result r:ss){
                 for(KeyValue kv : r.raw()){
                    System.out.print(new String(kv.getRow()) + " ");
                    System.out.print(new String(kv.getFamily()) + ":");
                    System.out.print(new String(kv.getQualifier()) + " ");
                    System.out.print(kv.getTimestamp() + " ");
                    System.out.println(new String(kv.getValue()));
                 }
             }
        } catch (IOException e){
            e.printStackTrace();
        }
    }

    public static void main (String [] agrs) {
        try {
            String tablename = "scores";
            String[] familys = {"grade", "course"};
            HBaseTest.creatTable(tablename, familys);

            //add record zkb
            HBaseTest.addRecord(tablename,"zkb","grade","","5");
            HBaseTest.addRecord(tablename,"zkb","course","","90");
            HBaseTest.addRecord(tablename,"zkb","course","math","97");
            HBaseTest.addRecord(tablename,"zkb","course","art","87");
            //add record baoniu
            HBaseTest.addRecord(tablename,"baoniu","grade","","4");
            HBaseTest.addRecord(tablename,"baoniu","course","math","89");

            System.out.println("===========get one record========");
            HBaseTest.getOneRecord(tablename, "zkb");

            System.out.println("===========show all record========");
            HBaseTest.getAllRecord(tablename);

            System.out.println("===========del one record========");
            HBaseTest.delRecord(tablename, "baoniu");
            HBaseTest.getAllRecord(tablename);

            System.out.println("===========show all record========");
            HBaseTest.getAllRecord(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}