hbase（三）Java操作 hbase（基础版本）

一、导入数据

create_namespace 'exam'
create 'exam:mytest','info'

hdfs dfs -put /opt/data/quizz/UserBehaviorTestHbase.csv  /quizz/data

hbase org.apache.hadoop.hbase.mapreduce.ImportTsv 
-Dimporttsv.separator="," 
-Dimporttsv.columns="HBASE_ROW_KEY,info:stuid,info:proid,info:level,info:score" 
exam:mytest /quizz/data/UserBehaviorTestHbase.csv

二、pom依赖导入

<dependency>
   <groupId>org.apache.hbase</groupId>
   <artifactId>hbase-client</artifactId>
   <version>1.2.0</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.apache.hbase/hbase-common -->
<dependency>
   <groupId>org.apache.hbase</groupId>
   <artifactId>hbase-common</artifactId>
   <version>1.2.0</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.apache.hbase/hbase-server -->
<dependency>
   <groupId>org.apache.hbase</groupId>
   <artifactId>hbase-server</artifactId>
   <version>1.2.0</version>
</dependency>

三、代码操作

 使用到工厂模式创建Connection连接，见 https://www.cnblogs.com/sabertobih/p/14001250.html

1）配置

//构建配置文件对象
Configuration conf = HBaseConfiguration.create();
//设置zookeeper端口
conf.set("hbase.zookeeper.property.clientPort","2181");
//设置zookeeper host
conf.set("hbase.zookeeper.quorum","192.168.56.111");
//设置hbase hmaster入口
conf.set("hbase.master","192.168.56.111:60000");    

2）创建表对象

//创建数据库连接对象
ConnectionBuilder<Connection> build = ConnectionFactory.getConnectionBuilder(DatabaseType.HBASE);
Connection conn = build.getConnection();
//根据表名查找表
Table tab = conn.getTable(TableName.valueOf("exam2:mt1"));        

3）put命令添加一行ROWKEY

//构建put命令对象并设置rowkey
Put put = new Put("3".getBytes());
//按照列族 修饰符 顺序填充一个列族的数据put.addColumn("info".getBytes(),"username".getBytes(),"ww".getBytes());
//put命令执行
tab.put(put);

4）get命令获得行数据

//设置一个get
Get get = new Get("1".getBytes());
//通过table直接获得该行数据
Result result = tab.get(get);
//通过列族和修饰符找到对应的值
String name = Bytes.toString(result.getValue("info".getBytes(), "username".getBytes()));
System.out.println(name);

5）设置scan，此处使用Filter过滤数据

//设置一个scan
SingleColumnValueFilter scvf = new SingleColumnValueFilter(
                "info".getBytes(),"username".getBytes(), CompareFilter.CompareOp.EQUAL,
                "ww".getBytes());
Scan scan = new Scan();
scan.setFilter(scvf);
ResultScanner rs = tab.getScanner(scan);
for (Result r : rs) {
   System.out.println(Bytes.toString(r.getRow())+":"+
   Bytes.toString(r.getValue("info".getBytes(),"username".getBytes())));
}