hbase学习笔记 第一篇

从今天开始学习hbase数据库，并每天记下自己的学习过程

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做hbase的开发，肯定不会是通过shell操作和hbase数据库，------>>>java api

（1）创建全局的configration对象，作用是在获得hbase的配置信息，从而和hmaster通信什么的

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

（2-1）创建表：

        HBaseAdmin admin = new HBaseAdmin(conf);       
        if (admin.tableExists(tableName)) {       
           //TODO 如弹出提示框什么的    
         } else {       
            HTableDescriptor tableDesc = new HTableDescriptor(tableName);       
            for(int i=0; i<familys.length; i++){       
                tableDesc.addFamily(new HColumnDescriptor(familys[i]));       
            }       
            admin.createTable(tableDesc);  

（2-2）删除表  ：

           HBaseAdmin admin = new HBaseAdmin(conf);      
           admin.disableTable(tableName);       
           admin.deleteTable(tableName);       

（2-3）插入一条记录  ：

public static void addRecord (String tableName, String rowKey, String family, String qualifier, String value)       
            throws Exception{      //参数的含义：表名 主键 列族 列名 数据 
        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();       
        }       
    }       

（2-4）删除一条记录  ： 根据主键删除

     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.");       
    }       

（2-5）查找数据  ：

         （2-5-1）查询所有数据

       HTablePool pool = new HTablePool(configuration, 1000);
        HTable table = (HTable) pool.getTable(tableName);
        ResultScanner rs = table.getScanner(new Scan());
	  for (Result r : rs) {
	    System.out.println("获得到rowkey:" + new String(r.getRow()));
		for (KeyValue keyValue : r.raw()) {
		  System.out.println("列：" + new String(keyValue.getFamily())
		  + "====值:" + new String(keyValue.getValue()));
				}
			}

            （2-5-2）根据主键查询

HTablePool pool = new HTablePool(configuration, 1000);
		HTable table = (HTable) pool.getTable(tableName);
		
			Get scan = new Get("abcdef".getBytes());// 根据rowkey查询
			Result r = table.get(scan);
			System.out.println("获得到rowkey:" + new String(r.getRow()));
			for (KeyValue keyValue : r.raw()) {
				System.out.println("列：" + new String(keyValue.getFamily())
						+ "====值:" + new String(keyValue.getValue()));
			}

            （2-5-3）单条件查询------------>>>通过Filter对象完成的

HTablePool pool = new HTablePool(configuration, 1000);
			HTable table = (HTable) pool.getTable(tableName);
			Filter filter = new SingleColumnValueFilter(
					Bytes.toBytes("column1"), null, CompareOp.EQUAL,
					Bytes.toBytes("aaa")); // 当列column1的值为aaa时进行查询
			Scan s = new Scan();
			s.setFilter(filter);
			ResultScanner rs = table.getScanner(s);
			for (Result r : rs) {
				System.out.println("获得到rowkey:" + new String(r.getRow()));
				for (KeyValue keyValue : r.raw()) {
					System.out.println("列：" + new String(keyValue.getFamily())
							+ "====值:" + new String(keyValue.getValue()));
				}
			}

        （2-5-4）多条件查询：方法同上，几个不同的filter实现

	HTablePool pool = new HTablePool(configuration, 1000);
			HTable table = (HTable) pool.getTable(tableName);

			List<Filter> filters = new ArrayList<Filter>();

			Filter filter1 = new SingleColumnValueFilter(
					Bytes.toBytes("column1"), null, CompareOp.EQUAL,
					Bytes.toBytes("aaa"));
			filters.add(filter1);

			Filter filter2 = new SingleColumnValueFilter(
					Bytes.toBytes("column2"), null, CompareOp.EQUAL,
					Bytes.toBytes("bbb"));
			filters.add(filter2);

			Filter filter3 = new SingleColumnValueFilter(
					Bytes.toBytes("column3"), null, CompareOp.EQUAL,
					Bytes.toBytes("ccc"));
			filters.add(filter3);

			FilterList filterList1 = new FilterList(filters);

			Scan scan = new Scan();
			scan.setFilter(filterList1);
			ResultScanner rs = table.getScanner(scan);
			for (Result r : rs) {
				System.out.println("获得到rowkey:" + new String(r.getRow()));
				for (KeyValue keyValue : r.raw()) {
					System.out.println("列：" + new String(keyValue.getFamily())
							+ "====值:" + new String(keyValue.getValue()));
				}
			}
			rs.close();