Eclipse HBase Java 客户端编程

本文以HBase 0.90.2为例，介绍如何在Windows系统，Eclipse IDE集成环境下，使用Java语言，进行HBase客户端编程，包含建立表、删除表、插入记录、删除记录、各种方式下的查询操作等。

1. 准备工作

1、下载后安装jdk包（这里使用的是jdk-6u10-rc2-bin-b32-windows-i586-p-12_sep_2008）；

2、下载eclipse，解压到本地（这里使用的是eclipse-java-helios-SR2-win32）；

3、下载HBase包，解压安装包到本地（这里使用的是hbase-0.90.2）。

2. 搭建开发环境

1、运行Eclipse，创建一个新的Java工程“HBaseClient”，右键项目根目录，选择“Properties”->“Java Build Path”->“Library”->“Add External JARs”，将HBase解压后根目录下的hbase-0.90.2.jar、hbase-0.90.2-tests.jar和lib子目录下所有jar包添加到本工程的Classpath下，如图1所示。

图1 Eclilse IDE下添加HBase的Jar包

2、在HBaseClient工程下创建一个文件夹，可以命名为Conf,去Hbase的配置文件夹内将hbase-site.xml拷贝，粘贴至你所创建的Conf文件夹中。右击工程，Properties,Java Build Path, Libraries, Add Class Folder，勾选出Conf，将自己所连接的HBase的配置文件hbase-site.xml添加到本工程的Classpath中，如下所示为配置文件的一个示例。

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< configuration > < property > < name >hbase.rootdir</ name > < value >hdfs://hostname:9000/hbase</ value > </ property > < property > < name >hbase.cluster.distributed</ name > < value >true</ value > </ property > < property > < name >hbase.zookeeper.quorum</ name > < value >*.*.*.*, *.*.*.*, *.*.*.*</ value > </ property > < property skipInDoc = "true" > < name >hbase.defaults.for.version</ name > < value >0.90.2</ value > </ property > </ configuration >

3、下面可以在Eclipse环境下进行HBase编程了。

3. HBase基本操作代码示例

3.1 初始化配置

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

3.2 创建表

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/**   * 创建表操作   * @throws IOException   */ public void createTable(String tablename, String[] cfs) throws IOException {      HBaseAdmin admin = new HBaseAdmin(conf);      if (admin.tableExists(tablename)) {          System.out.println( "表已经存在！" );      }      else {          HTableDescriptor tableDesc = new HTableDescriptor(tablename);          for ( int i = 0 ; i < cfs.length; i++) {              tableDesc.addFamily( new HColumnDescriptor(cfs[i]));          }          admin.createTable(tableDesc);          System.out.println( "表创建成功！" );      } }

3.3 删除表

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/**   * 删除表操作   * @param tablename   * @throws IOException   */ public void deleteTable(String tablename) throws IOException {      try {          HBaseAdmin admin = new HBaseAdmin(conf);          admin.disableTable(tablename);          admin.deleteTable(tablename);          System.out.println( "表删除成功！" );      } catch (MasterNotRunningException e) {          e.printStackTrace();      } catch (ZooKeeperConnectionException e) {          e.printStackTrace();      } }

3.4 插入一行记录

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/**   * 插入一行记录   * @param tablename   * @param cfs   */ public void writeRow(String tablename, String[] cfs) {      try {          HTable table = new HTable(conf, tablename);          Put put = new Put(Bytes.toBytes( "rows1" ));          for ( int j = 0 ; j < cfs.length; j++) {              put.add(Bytes.toBytes(cfs[j]),                      Bytes.toBytes(String.valueOf( 1 )),                      Bytes.toBytes( "value_1" ));              table.put(put);          }      } catch (IOException e) {          e.printStackTrace();      } }

3.5 删除一行记录

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/**   * 删除一行记录   * @param tablename   * @param rowkey   * @throws IOException   */ public void deleteRow(String tablename, String rowkey) throws IOException {      HTable table = new HTable(conf, tablename);      List list = new ArrayList();      Delete d1 = new Delete(rowkey.getBytes());      list.add(d1);      table.delete(list);      System.out.println( "删除行成功！" ); }

3.6 查找一行记录

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/**   * 查找一行记录   * @param tablename   * @param rowkey   */ public static void selectRow(String tablename, String rowKey)          throws IOException {      HTable table = new HTable(conf, tablename);      Get g = new Get(rowKey.getBytes());      Result rs = table.get(g);      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()));      } }

3.7 查询表中所有行

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/**   * 查询表中所有行   * @param tablename   */ public void scaner(String tablename) {      try {          HTable table = new HTable(conf, tablename);          Scan s = new Scan();          ResultScanner rs = table.getScanner(s);          for (Result r : rs) {              KeyValue[] kv = r.raw();              for ( int i = 0 ; i < kv.length; i++) {                  System.out.print( new String(kv[i].getRow()) + "  " );                  System.out.print( new String(kv[i].getFamily()) + ":" );                  System.out.print( new String(kv[i].getQualifier()) + "  " );                  System.out.print(kv[i].getTimestamp() + "  " );                  System.out.println( new String(kv[i].getValue()));              }          }      } catch (IOException e) {          e.printStackTrace();      } }

 

4. 一个小例子

package org.apache.test;

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 HBaseBasic {
  
    private static Configuration conf = null;
   
   
    static {
        Configuration HBASE_CONFIG = new Configuration();
        //与hbase/conf/hbase-site.xml中hbase.zookeeper.quorum配置的值相同 
        HBASE_CONFIG.set("hbase.zookeeper.quorum", "192.168.1.1");
        //与hbase/conf/hbase-site.xml中hbase.zookeeper.property.clientPort配置的值相同
        HBASE_CONFIG.set("hbase.zookeeper.property.clientPort", "2181");
        conf = HBaseConfiguration.create(HBASE_CONFIG);
    }
   
    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.");
        } 
    }
  
   
    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();
       }
    }
   
   
    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();
     }
    }

   
    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.");
    }
   
   
    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()));
     }
    }
   
   
    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 = "student";
   String[] familys = {"id", "name","score"};
   //HBaseBasic.creatTable(tablename, familys);
   
   //add record zkb
   //HBaseBasic.addRecord(tablename,"2","id","","095832");
   //HBaseBasic.addRecord(tablename,"2","name","","zmac");
   //HBaseBasic.addRecord(tablename,"2","score","math","97");
   //HBaseBasic.addRecord(tablename,"2","score","chinese","87");
   //HBaseBasic.addRecord(tablename,"2","score","english","85");
   //add record  baoniu
   
   System.out.println("===========get one record========");
   HBaseBasic.getOneRecord(tablename, "2");
   
   System.out.println("===========show all record========");
   HBaseBasic.getAllRecord(tablename);
   
   System.out.println("===========del one record========");
   HBaseBasic.delRecord(tablename, "2");
   HBaseBasic.getAllRecord(tablename);
   
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
}
运行会，你将看到首先创建数据库student,其字段为id,name,score{english,math,chinese}，然后向该数据表插入数据，再查询记录，删除记录等。