Hbase經常使用操做CRUD(增刪改查)

參考：

http://blog.csdn.net/net19880504/article/details/17733161

 

運行Eclipse，建立一個新的Java工程「HBaseClient」，右鍵項目根目錄，選擇 「Properties」->「Java Build Path」->「Library」->「Add External JARs」，將Hbase解壓後根目錄下的hbase-0.94.1-security.jar、hbase-0.94.1-security-tests.jar和lib子目錄下全部jar 包添加到本工程的Classpath下。

HBase提供了java api來對HBase進行一系列的管理涉及到對錶的管理、數據的操做等。經常使用的API操做有：

　　一、 對錶的建立、刪除、顯示以及修改等，能夠用HBaseAdmin，一旦建立了表，那麼能夠經過HTable的實例來訪問表，每次能夠往表裏增長數據。

　　二、 插入數據

　　　　建立一個Put對象，在這個Put對象裏能夠指定要給哪一個列增長數據，以及當前的時間戳等值，而後經過調用HTable.put(Put)來提交操做，子猴在這裏提請注意的是：在建立Put對象的時候，你必須指定一個行(Row)值，在構造Put對象的時候做爲參數傳入。

　　三、 獲取數據

　　　　要獲取數據，使用Get對象，Get對象同Put對象同樣有好幾個構造函數，一般在構造的時候傳入行值，表示取第幾行的數據，經過HTable.get(Get)來調用。

　　四、 瀏覽每一行

　　　　經過Scan能夠對錶中的行進行瀏覽，獲得每一行的信息，好比列名，時間戳等，Scan至關於一個遊標，經過next()來瀏覽下一個，經過調用HTable.getScanner(Scan)來返回一個ResultScanner對象。HTable.get(Get)和HTable.getScanner(Scan)都是返回一個Result。Result是一個

KeyValue的鏈表。

　　五、 刪除

　　　　使用Delete來刪除記錄，經過調用HTable.delete(Delete)來執行刪除操做。（注：刪除這裏有些特別，也就是刪除並非立刻將數據從表中刪除。）

　　六、 鎖

　　　　新增、獲取、刪除在操做過程當中會對所操做的行加一個鎖，而瀏覽卻不會。

　　七、 簇的訪問

　　　　客戶端代碼經過ZooKeeper來訪問找到簇，也就是說ZooKeeper quorum將被使用，那麼相關的類（包）應該在客戶端的類（classes）目錄下，即客戶端必定要找到文件hbase-site.xml。 

     新建一個類：

 

  1 package com.hj.myhbase131;
  2 
  3 import java.io.IOException;
  4 import java.util.ArrayList;
  5 import java.util.List;
  6 
  7 import org.apache.hadoop.conf.Configuration;
  8 import org.apache.hadoop.hbase.client.Put;
  9 import org.apache.hadoop.hbase.client.Result;
 10 import org.apache.hadoop.hbase.client.ResultScanner;
 11 import org.apache.hadoop.hbase.client.Scan;
 12 import org.apache.hadoop.hbase.util.Bytes;
 13 import org.apache.hadoop.hbase.Cell;
 14 import org.apache.hadoop.hbase.CellUtil;
 15 import org.apache.hadoop.hbase.HBaseConfiguration;
 16 import org.apache.hadoop.hbase.HColumnDescriptor;
 17 import org.apache.hadoop.hbase.HTableDescriptor;
 18 import org.apache.hadoop.hbase.TableName;
 19 import org.apache.hadoop.hbase.client.Connection;
 20 import org.apache.hadoop.hbase.client.ConnectionFactory;
 21 import org.apache.hadoop.hbase.client.Delete;
 22 import org.apache.hadoop.hbase.client.Get;
 23 import org.apache.hadoop.hbase.client.HBaseAdmin;
 24 import org.apache.hadoop.hbase.client.HTable;
 25 
 26 /**
 27  * Hello world!
 28  *
 29  */
 30 public class App 
 31 {
 32     private static Configuration conf = null;
 33     private static Connection conn = null;
 34     
 35     static {
 36         conf = HBaseConfiguration.create();
 37         try {
 38             conn = ConnectionFactory.createConnection(conf);
 39         } catch (IOException e) {
 40             // TODO Auto-generated catch block
 41             e.printStackTrace();
 42         }
 43     }
 44     
 45     /**建立表
 46      * @param tableName
 47      * @param familys
 48      * @throws Exception
 49      */
 50     public static void creatTable(String tableName, String[] familys) throws Exception {
 51         HBaseAdmin admin = (HBaseAdmin) conn.getAdmin();
 52         if (admin.tableExists(tableName)) {
 53             System.out.println("table already exists");
 54         }else {
 55             HTableDescriptor tableDesc = new HTableDescriptor(TableName.valueOf(tableName));
 56             for (int i = 0; i < familys.length; i++) {
 57                 tableDesc.addFamily(new HColumnDescriptor(familys[i]));
 58             }
 59             admin.createTable(tableDesc);
 60             System.out.println("create table " + tableName + " ok."); 
 61         }
 62     }
 63     
 64     /**刪除表
 65      * @param tableName
 66      * @throws Exception
 67      */
 68     public static void deleteTable(String tableName) throws Exception {
 69         HBaseAdmin admin = (HBaseAdmin) conn.getAdmin();
 70         admin.disableTable(tableName);
 71         admin.deleteTable(tableName);
 72         System.out.println("delete table " + tableName + " ok."); 
 73     }
 74          
 75     /**插入一行記錄
 76      * @param tableName
 77      * @param rowKey
 78      * @param family
 79      * @param qualifier
 80      * @param value
 81      * @throws Exception
 82      */
 83     public static void addRecord (String tableName, String rowKey, String family, String qualifier, String value)       
 84             throws Exception{       
 85         try {       
 86             HTable table = (HTable) conn.getTable(TableName.valueOf(tableName));       
 87             Put put = new Put(Bytes.toBytes(rowKey));
 88             put.addColumn(Bytes.toBytes(family),Bytes.toBytes(qualifier),Bytes.toBytes(value));       
 89             table.put(put);       
 90             System.out.println("insert recored " + rowKey + " to table " + tableName +" ok.");       
 91         } catch (IOException e) {       
 92             e.printStackTrace();       
 93         }       
 94     }  
 95     
 96     /**    
 97      * 刪除一行記錄    
 98      */      
 99     public static void delRecord (String tableName, String rowKey) throws IOException{       
100         HTable table = (HTable) conn.getTable(TableName.valueOf(tableName));  
101         List <Delete>list = new ArrayList<Delete>();
102         Delete del = new Delete(rowKey.getBytes()); 
103         list.add(del);     
104         table.delete(list);       
105         System.out.println("del recored " + rowKey + " ok.");       
106     }       
107             
108     /**    
109      * 查找一行記錄    
110      */      
111     public static void getOneRecord (String tableName, String rowKey) throws IOException{       
112         HTable table = (HTable) conn.getTable(TableName.valueOf(tableName));         
113         Get get = new Get(rowKey.getBytes());       
114         Result rs = table.get(get);       
115         for(Cell cell : rs.listCells()){       
116             // 一個Cell就是一個單元格，經過下面的方法能夠得到這個單元格的各個值
117             System.out.print("行健: " + new String(CellUtil.cloneRow(cell)));
118             System.out.print("列簇: " + new String(CellUtil.cloneFamily(cell)));
119             System.out.print(" 列: " + new String(CellUtil.cloneQualifier(cell)));
120             System.out.print(" 值: " + new String(CellUtil.cloneValue(cell)));
121             System.out.println("時間戳: " + cell.getTimestamp());          
122         }       
123     }       
124             
125     /**    
126      * 顯示全部數據    
127      */      
128     public static void getAllRecord (String tableName) {       
129         try{       
130              HTable table = (HTable) conn.getTable(TableName.valueOf(tableName));        
131              Scan s = new Scan();       
132              ResultScanner ss = table.getScanner(s);       
133              for(Result r:ss){       
134                  for(Cell cell : r.listCells()){       
135                      System.out.print(Bytes.toString(CellUtil.cloneRow(cell)) + " " );       
136                      System.out.print(Bytes.toString(CellUtil.cloneFamily(cell)) + ":" );       
137                      System.out.print(Bytes.toString(CellUtil.cloneQualifier(cell)) + " " );       
138                      System.out.println(Bytes.toString(CellUtil.cloneValue(cell)));          
139                  }      
140              }       
141         } catch (IOException e){       
142             e.printStackTrace();       
143         }       
144     }
145     
146     public static void main( String[] args ) throws Exception
147     {
148         try {       
149             String tablename = "scores";       
150             String[] familys = {"grade", "course"};       
151             App.creatTable(tablename, familys);       
152                     
153             //add record zkb       
154             App.addRecord(tablename,"zkb","grade","","5");       
155             App.addRecord(tablename,"zkb","course","","90");       
156             App.addRecord(tablename,"zkb","course","math","97");       
157             App.addRecord(tablename,"zkb","course","art","87");       
158             //add record  baoniu       
159             App.addRecord(tablename,"baoniu","grade","","4");       
160             App.addRecord(tablename,"baoniu","course","math","89");       
161                     
162             System.out.println("===========get one record========");       
163             App.getOneRecord(tablename, "zkb");       
164                     
165             System.out.println("===========show all record========");       
166             App.getAllRecord(tablename);       
167                     
168             System.out.println("===========del one record========");       
169             App.delRecord(tablename, "baoniu");       
170             App.getAllRecord(tablename);       
171                     
172             System.out.println("===========show all record========");       
173             App.getAllRecord(tablename);       
174         } catch (Exception e) {       
175             e.printStackTrace();       
176         }       
177     }
178 }

 

結果顯示爲：

 

table already exists
insert recored zkb to table scores ok.
insert recored zkb to table scores ok.
insert recored zkb to table scores ok.
insert recored zkb to table scores ok.
insert recored baoniu to table scores ok.
insert recored baoniu to table scores ok.
===========get one record========
行健: zkb列簇: course 列:  值: 90時間戳: 1501034629784
行健: zkb列簇: course 列: art 值: 87時間戳: 1501034629794
行健: zkb列簇: course 列: math 值: 97時間戳: 1501034629787
行健: zkb列簇: grade 列:  值: 5時間戳: 1501034629768
===========show all record========
baoniu course:math 89
baoniu grade: 4
zkb course: 90
zkb course:art 87
zkb course:math 97
zkb grade: 5
===========del one record========
del recored baoniu ok.
zkb course: 90
zkb course:art 87
zkb course:math 97
zkb grade: 5
===========show all record========
zkb course: 90
zkb course:art 87
zkb course:math 97
zkb grade: 5