HBase入门教程

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# 背景

最近看到公司一个项目用到hbase，之前也一直想看下hbase。个人理解Hbase作为一个nosql数据库，逻辑模型感觉跟关系型数据库有点类似。一个table，有row即行，列。不过列是一个列族，可以放多个字段，类似下面这种格式

table users

行　　 | 列族　　　　 | value 　　　　| 　　列族　　 | 　　value

rows1 | info:name　 | zhangsan　　 | 　　....　　　 |　　...

rows1 | info:address | wudaokou　　 | 　　....　　　 |　　...

# 安装

说下安装吧，有三种模式：单机、伪分布式、集群。这里我用的单机，官网:https://hbase.apache.org/downloads.html

下载，解压

安装步骤一定要安装官网说明来，博客这些都太老了

1. hbase-env.sh设置JAVA_HOME

2. hbase-site.xml

<configuration>

  <property>

    <name>hbase.rootdir</name>

    <value>file:///Users/gxf/hbase</value>

  </property>

  <property>

    <name>hbase.zookeeper.property.dataDir</name>

    <value>/Users/gxf/zookeeper</value>

  </property>

  <property>

    <name>hbase.unsafe.stream.capability.enforce</name>

    <value>false</value>

    <description>

      Controls whether HBase will check for stream capabilities (hflush/hsync).

      Disable this if you intend to run on LocalFileSystem, denoted by a rootdir

      with the 'file://' scheme, but be mindful of the NOTE below.

      WARNING: Setting this to false blinds you to potential data loss and

      inconsistent system state in the event of process and/or node failures. If

      HBase is complaining of an inability to use hsync or hflush it's most

      likely not a false positive.

    </description>

  </property>

</configuration>

这里，安装和单机部署基本完成

$HBASE_HOME/bin/start-hbase.sh启动hbase

http://localhost:16010/master-status这个能正确显示即启动成功

# 使用

hbaset提供了一个命令行客户端，我们可以使用命令行客户端，创建、删除、修改、查询表，插入记录，插叙记录，删除记录，修改记录

$HBASE_HOME/bin/hbase shell

启动客户端，基本命令在官网也可以看，建议在官网看。我也是搬运工，顺便熟悉一下，做个备忘录

1. list命令，列出所有的表

list

2. 新建user表，列族为info，存放用户的基本信息

create 'user', 'info'

3. 删除表，要先disable，再drop

disable 'user'

drop 'user'

4. 插入数据, put 'tablename', 'row', 'cf:col', 'value'

put 'user', 'row1', 'info:name', 'guanxianseng'

5. 查询数据 scan tablenanme

scan 'user'

# java客户端

pom.xml

<dependencies>

    <dependency>

      <groupId>org.apache.hbase</groupId>

      <artifactId>hbase-client</artifactId>

      <version>1.4.8</version>

    </dependency>

    <dependency>

      <groupId>org.apache.hbase</groupId>

      <artifactId>hbase</artifactId>

      <version>1.4.8</version>

    </dependency>

    <!-- log -->

    <dependency>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-api</artifactId>

      <version>1.7.25</version>

    </dependency>

    <dependency>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-log4j12</artifactId>

      <version>1.8.0-beta2</version>

    </dependency>

    <dependency>

      <groupId>org.apache.logging.log4j</groupId>

      <artifactId>log4j-slf4j-impl</artifactId>

      <version>2.11.0</version>

    </dependency>

    <dependency>

      <groupId>org.apache.logging.log4j</groupId>

      <artifactId>log4j-core</artifactId>

      <version>2.11.1</version>

    </dependency>

    <dependency>

      <groupId>org.apache.logging.log4j</groupId>

      <artifactId>log4j-api</artifactId>

      <version>2.11.1</version>

    </dependency>

  </dependencies>

这里我用了log,所有加了log4j等log依赖

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.Cell;

import org.apache.hadoop.hbase.CellUtil;

import org.apache.hadoop.hbase.HBaseConfiguration;

import org.apache.hadoop.hbase.HColumnDescriptor;

import org.apache.hadoop.hbase.HTableDescriptor;

import org.apache.hadoop.hbase.TableName;

import org.apache.hadoop.hbase.client.Admin;

import org.apache.hadoop.hbase.client.Connection;

import org.apache.hadoop.hbase.client.ConnectionFactory;

import org.apache.hadoop.hbase.client.Delete;

import org.apache.hadoop.hbase.client.Get;

import org.apache.hadoop.hbase.client.Put;

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.Table;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

public class HBaseTest {

  private static Configuration conf = null;

  private static Connection connection = null;

  private static Admin admin = null;

  private static Logger logger = LoggerFactory.getLogger(HBaseTest.class);

  static {

    //设置连接信息

    conf = HBaseConfiguration.create();

    conf.set("hbase.zookeeper.quorum", "localhost");

    conf.set("hbase.zookeeper.property.clientPort", "2181");

    conf.setInt("hbase.rpc.timeout", 2000);

    conf.setInt("hbase.client.operation.timeout", 3000);

    conf.setInt("hbase.client.scanner.timeout.period", 6000);

    try {

      connection = ConnectionFactory.createConnection(conf);

      admin = connection.getAdmin();

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

  public static void main(String[] args) throws Exception {

    String tableName = "test3";

    String[] colFam = new String[]{"colFam"};

//    createTable(tableName, colFam);

//    deleteTable(tableName);

//    listTables();

//    addData("users", "row3", "info", "name", "guanxianseng");

//    deleteData("users", "row1", "info", "name");

//    query("users", "row2", "info", "name");

    scan("users", "row1", "row2");

  }

  /**

   * scan数据

   * */

  public static void scan(String tableNameStr, String startRowKey, String stopRowKey)

      throws IOException {

    Table table = connection.getTable(TableName.valueOf(tableNameStr));

    Scan scan = new Scan();

    ResultScanner resultScanner = table.getScanner(scan);

    for(Result result : resultScanner){

      showCell(result);

    }

  }

  /**

   * 查询数据

   * */

  public static void query(String tableNameStr, String rowkey, String colFam, String col)

      throws IOException {

    Table table = connection.getTable(TableName.valueOf(tableNameStr));

    Get get = new Get(rowkey.getBytes());

    Result result = table.get(get);

    showCell(result);

  }

  /**

   * 打印一个cell所有数据

   * */

  private static void showCell(Result result){

    for(Cell cell : result.rawCells()){

      logger.info("rawname:{}, timestamp:{}, colFam:{}, colName:{}, value:{}", new String(CellUtil.cloneRow(cell)), cell.getTimestamp(),

                  new String(CellUtil.cloneFamily(cell)), new String(CellUtil.cloneQualifier(cell)), new String(CellUtil.cloneValue(cell)));

    }

  }

  /**

   * 删除数据

   * */

  public static void deleteData(String tableNameStr, String row,  String colFam, String col) throws IOException {

    Table table = connection.getTable(TableName.valueOf(tableNameStr));

    Delete delete = new Delete(row.getBytes());

    table.delete(delete);

    logger.info("delete tablename: {}, row:{}, colFam:{}, col:{}", tableNameStr, row, colFam, col);

  }

  /**

   * 向表中插入数据

   * */

  public static void addData(String tableNameStr, String rowkey, String colFam, String col, String value)

      throws IOException {

    TableName tableName = TableName.valueOf(tableNameStr);

    Table table = connection.getTable(tableName);

    Put put = new Put(rowkey.getBytes());

    put.addColumn(colFam.getBytes(), col.getBytes(), value.getBytes());

    table.put(put);

    table.close();

    logger.info("put table:{}, rowkey:{}, colFam:{}, col:{}, value:{}", tableNameStr, rowkey, colFam, col, value);

  }

  /**

   * 列出所有的表

   * */

  public static void listTables() throws IOException {

    HTableDescriptor[] hTableDescriptors = admin.listTables();

    for(HTableDescriptor hTableDescriptor : hTableDescriptors){

      logger.info("table :{}", hTableDescriptor.getTableName());

    }

  }

  /**

   * 创建表

   */

  public static void createTable(String tableNameStr, String[] colFam) {

    try {

      TableName tableName = TableName.valueOf(tableNameStr);

      Table table = connection.getTable(tableName);

      if (admin.tableExists(tableName)) {

        //表已经存在

        logger.info("table {} already exist", tableNameStr);

      } else {

        //表不存在

        HTableDescriptor hTableDescriptor = new HTableDescriptor(tableNameStr);

        for (String colStr : colFam) {

          HColumnDescriptor columnDescriptor = new HColumnDescriptor(colStr);

          hTableDescriptor.addFamily(columnDescriptor);

        }

        admin.createTable(hTableDescriptor);

        logger.info("creat table success");

        admin.close();

      }

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

  /**

   * 删除表 1. disable 2. delete

   */

  public static void deleteTable(String tableNameStr) throws Exception {

    TableName tableName = TableName.valueOf(tableNameStr);

    if (!admin.tableExists(tableName)) {

      logger.error("table :{} not exist", tableNameStr);

    } else {

      admin.disableTable(tableName);

      admin.deleteTable(tableName);

      logger.info("delete table:{}", tableNameStr);

    }

  }

}