Hbase-1.2.4 javaAPI操作总结

一、 概述
关于Hbase的工作原理网上已经有很多详细介绍，就不在这里赘述了，我们直接研究代码

作为Hbase最新stable版，Hbase内部引入的部分hadoop2.5系列的jar包，这里且暂不去理会它，但是Java环境必须要8以上，我的正确运行环境为：
Centos-6.5
hadoop-2.6.5
Hbase-1.2.4
jdk1.8
二、代码设计

package com.unisk.bigdata.hbase;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.hbase.HBaseConfiguration;import org.apache.hadoop.hbase.HColumnDescriptor;import org.apache.hadoop.hbase.HConstants;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.HTable;import org.apache.hadoop.hbase.client.Put;import org.apache.hadoop.hbase.io.compress.Compression.Algorithm;import org.apache.hadoop.hbase.util.Bytes;public class Hbase {    private static final String TABLE_NAME = "PEOPLE";    private static final String COLUMN_FAMILY = "baseINFO";    public static void createOrOverwrite(Admin admin, HTableDescriptor table) throws IOException {        if (admin.tableExists(table.getTableName())) {          admin.disableTable(table.getTableName());          admin.deleteTable(table.getTableName());        }        admin.createTable(table);      }    public static void createSchemaTables(Configuration config) throws IOException {        Connection connection = ConnectionFactory.createConnection(config);             Admin admin = connection.getAdmin();          HTableDescriptor table = admin.getTableDescriptor(TableName.valueOf(TABLE_NAME));          table.addFamily(new HColumnDescriptor(COLUMN_FAMILY).setCompressionType(Algorithm.NONE));          System.out.println("Creating table......");          createOrOverwrite(admin, table);          System.out.println("Done.");      }    @SuppressWarnings("deprecation")    public static void insert(Configuration conf)throws IOException{        HTable table = new HTable(conf,TABLE_NAME.getBytes());        Put put = new Put(Bytes.toBytes("0001"));        put.add("baseINFO".getBytes(), "name".getBytes(), "wangxiaoming".getBytes());        put.setAttribute("name", "wxm".getBytes());        table.setWriteBufferSize(1024*1024*1024);        table.put(put);        System.out.println("insert success!");        table.close();    }    public static void modifySchema (Configuration conf) throws IOException {            Connection connection = ConnectionFactory.createConnection(conf);                 Admin admin = connection.getAdmin();              TableName tableName = TableName.valueOf(TABLE_NAME);              if (!admin.tableExists(tableName)) {                System.out.println("Table does not exist.");                System.exit(-1);              }              HTableDescriptor table = admin.getTableDescriptor(tableName);              // Update existing table              HColumnDescriptor newColumn = new HColumnDescriptor("NEWCF");              newColumn.setCompactionCompressionType(Algorithm.GZ);              newColumn.setMaxVersions(HConstants.ALL_VERSIONS);              admin.addColumn(tableName, newColumn);              // Update existing column family              HColumnDescriptor existingColumn = new HColumnDescriptor(COLUMN_FAMILY);              existingColumn.setCompactionCompressionType(Algorithm.GZ);              existingColumn.setMaxVersions(HConstants.ALL_VERSIONS);              table.modifyFamily(existingColumn);              admin.modifyTable(tableName, table);              // Disable an existing table              admin.disableTable(tableName);              // Delete an existing column family              admin.deleteColumn(tableName, COLUMN_FAMILY.getBytes("UTF-8"));              // Delete a table (Need to be disabled first)              admin.deleteTable(tableName);      }    public static void main(String... args) throws IOException {        Configuration config = HBaseConfiguration.create();      //Add any necessary configuration files (hbase-site.xml, core-site.xml)      //config.addResource(new Path(System.getenv("HBASE_CONF_DIR"), "hbase-site.xml"));      //config.addResource(new Path(System.getenv("HADOOP_CONF_DIR"), "core-site.xml"));      config.addResource("/wxm/software/hbase/hbase-1.2.4/conf/hbase-site.xml");      config.addResource("/wxm/software/hbase/hbase-1.2.4/conf/core-site.xml");      createSchemaTables(config);      insert(config);       //modifySchema(config);      }  }

三、代码分析

为了逻辑上严谨一点，这里写了createOrOverwrite方法，若初学API，大可不必浪费这几行空间，升级1.0之后，不建议使用HTablePool对象，可使用Admin来跟Hbase交互，另在main方法中，因为运行调用Hbase环境配置，故需要加入运行时参数，但简单起见，依然可以固定在代码里，关于put对象，以及HTableDescripter对象，可以以集合的形式传入从而增加效率，这个看需求，后期改进即可，后面如果有时间，我会将关于Hbase的通用增删改查的工具发布到github，大家有问题可以加qq1821088755一起交流。