hbase java api操作

HBase提供了对HBase进行一系列的管理涉及到对表的管理、数据的操作java api。

常用的API操作有： 
　　1、  对表的创建、删除、显示以及修改等，可以用HBaseAdmin，一旦创建了表，那么可以通过HTable的实例来访问表，每次可以往表里增加数据。 
　　2、  插入数据 
　　　　创建一个Put对象，在这个Put对象里可以指定要给哪个列增加数据，以及当前的时间戳等值，然后通过调用HTable.put(Put)来提交操作，子猴在这里提请注意的是：在创建Put对象的时候，你必须指定一个行(Row)值，在构造Put对象的时候作为参数传入。 
　　3、  获取数据 
　　　　要获取数据，使用Get对象，Get对象同Put对象一样有好几个构造函数，通常在构造的时候传入行值，表示取第几行的数据，通过HTable.get(Get)来调用。 
　　4、  浏览每一行 
　　　　通过Scan可以对表中的行进行浏览，得到每一行的信息，比如列名，时间戳等，Scan相当于一个游标，通过next()来浏览下一个，通过调用HTable.getScanner(Scan)来返回一个ResultScanner对象。HTable.get(Get)和HTable.getScanner(Scan)都是返回一个Result。Result是一个 
KeyValue的链表。 
　　5、  删除 
　　　　使用Delete来删除记录，通过调用HTable.delete(Delete)来执行删除操作。（注：删除这里有些特别，也就是删除并不是马上将数据从表中删除。） 
　　6、  锁 
　　　　新增、获取、删除在操作过程中会对所操作的行加一个锁，而浏览却不会。 
　　7、  簇的访问 
　　　　客户端代码通过ZooKeeper来访问找到簇，也就是说ZooKeeper quorum将被使用，那么相关的类（包）应该在客户端的类（classes）目录下，即客户端一定要找到文件hbase-site.xml。 

 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 {
         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", "10.1.1.1");
         //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);
     }

     /**
      * 创建一张表
      */
     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.");
         }
     }

     /**
      * 删除表
      */
     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();
        }
     }

     /**
      * 插入一行记录
      */
     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();
         }
     }

     /**
      * 删除一行记录
      */
     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.");
     }

     /**
      * 查找一行记录
      */
     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()));
         }
     }

     /**
      * 显示所有数据
      */
     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();
         }
     }
 }