HBase开发操作

1.配置

HBaseConfiguration
包：org.apache.hadoop.hbase.HBaseConfiguration
作用：通过此类可以对HBase进行配置
用法实例：
Configuration config = HBaseConfiguration.create();
说明： HBaseConfiguration.create() 默认会从classpath 中查找 hbase-site.xml 中的配置信息，初始化 Configuration。

使用方法:

static Configuration config = null;
static {
     config = HBaseConfiguration.create();
     config.set("hbase.zookeeper.quorum", "slave1,slave2,slave3");
     config.set("hbase.zookeeper.property.clientPort", "2181");
}

2.表管理类

HBaseAdmin
包：org.apache.hadoop.hbase.client.HBaseAdmin
作用：提供接口关系HBase 数据库中的表信息

用法：
HBaseAdmin admin = new HBaseAdmin(config);

3.表描述类

HTableDescriptor
包：org.apache.hadoop.hbase.HTableDescriptor
作用：HTableDescriptor 类包含了表的名字以及表的列族信息
表的schema（设计）
用法：

HTableDescriptor htd =new HTableDescriptor(tablename);
htd.addFamily(new HColumnDescriptor(“myFamily”));

4.列族的描述类

HColumnDescriptor
包：org.apache.hadoop.hbase.HColumnDescriptor
作用：HColumnDescriptor 维护列族的信息

用法：
htd.addFamily(new HColumnDescriptor(“myFamily”));

5.创建表的操作

CreateTable（一般我们用shell创建表）
static Configuration config = null;
static {
     config = HBaseConfiguration.create();
     config.set("hbase.zookeeper.quorum", "slave1,slave2,slave3");
     config.set("hbase.zookeeper.property.clientPort", "2181");
}

HBaseAdmin admin = new HBaseAdmin(config);
HTableDescriptor desc = new HTableDescriptor(tableName);
HColumnDescriptor family1 = new HColumnDescriptor(“f1”);
HColumnDescriptor family2 = new HColumnDescriptor(“f2”);
desc.addFamily(family1);
desc.addFamily(family2);
admin.createTable(desc);

6.删除表

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

6.HTable

包：org.apache.hadoop.hbase.client.HTable
作用：HTable 和 HBase 的表通信
用法：

// 普通获取表
 HTable table = new HTable(config,Bytes.toBytes(tablename);
// 通过连接池获取表
Connection connection = ConnectionFactory.createConnection(config);
HTableInterface table = connection.getTable(TableName.valueOf("user"));

8.单条插入数据

Put
包：org.apache.hadoop.hbase.client.Put
作用：插入数据
用法：

Put put = new Put(row);
p.add(family,qualifier,value);

说明：向表 tablename 添加 “family,qualifier,value”指定的值。

示例代码：

Connection connection = ConnectionFactory.createConnection(config);
HTableInterface table = connection.getTable(TableName.valueOf("user"));
Put put = new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier),Bytes.toBytes(value));
table.put(put);

9.批量插入

批量插入

List<Put> list = new ArrayList<Put>();
Put put = new Put(Bytes.toBytes(rowKey));//获取put，用于插入
put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier),Bytes.toBytes(value));//封装信息
list.add(put);
table.put(list);//添加记录

10.删除数据

Delete
包：org.apache.hadoop.hbase.client.Delete
作用：删除给定rowkey的数据
用法：

Delete del= new Delete(Bytes.toBytes(rowKey));
table.delete(del);

代码实例

Connection connection = ConnectionFactory.createConnection(config);
HTableInterface table = connection.getTable(TableName.valueOf("user"));
Delete del= new Delete(Bytes.toBytes(rowKey));
table.delete(del);

11.单条查询

Get
包：org.apache.hadoop.hbase.client.Get
作用：获取单个行的数据
用法：

HTable table = new HTable(config,Bytes.toBytes(tablename));
Get get = new Get(Bytes.toBytes(row));
Result result = table.get(get);

说明：获取 tablename 表中 row 行的对应数据

代码示例：

Connection connection = ConnectionFactory.createConnection(config);
HTableInterface table = connection.getTable(TableName.valueOf("user"));
Get get = new Get(rowKey.getBytes());
Result row = table.get(get);
for (KeyValue kv : row.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(new String(kv.getValue()));
    System.out.print(" timestamp = " + kv.getTimestamp() + "\n");
}

12.批量查询

ResultScanner
包：org.apache.hadoop.hbase.client.ResultScanner
作用：获取值的接口
用法：

ResultScanner scanner = table.getScanner(scan);
For(Result rowResult : scanner){
        Bytes[] str = rowResult.getValue(family,column);
}

说明：循环获取行中列值。

代码示例：

Connection connection = ConnectionFactory.createConnection(config);
HTableInterface table = connection.getTable(TableName.valueOf("user"));
Scan scan = new Scan();
scan.setStartRow("a1".getBytes());
scan.setStopRow("a20".getBytes());
ResultScanner scanner = table.getScanner(scan);
for (Result row : scanner) {
    System.out.println("\nRowkey: " + new String(row.getRow()));
    for (KeyValue kv : row.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(new String(kv.getValue()));
         System.out.print(" timestamp = " + kv.getTimestamp() + "\n");
    }
}