学完hbase shell API的基本操作之后，可以通过Java API 对hbase基本操作实现一把。

1. 基本概念

2.首先封装一个hbase connection工具类，这是一个单例的类，用于获取获取连接，关闭连接，获取hbase table对象。

package com.zsk.hbase.api;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Table;

import java.io.IOException;

public class HBaseConn {
    private static final HBaseConn INSTANCE = new HBaseConn();
    private static  Configuration configuration; //hbase配置
    private static  Connection connection; //hbase connection
    private HBaseConn(){
        try{
            if (configuration==null){
                 configuration = HBaseConfiguration.create();
                 configuration.set("hbase.zookeeper.quorum","192.168.217.129:2181");
            }

        }catch (Exception e){
            e.printStackTrace();
        }
    }
    private  Connection getConnection(){
        if (connection==null || connection.isClosed()){
            try{
                connection = ConnectionFactory.createConnection(configuration);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        return connection;
    }
    public static Connection getHBaseConn(){
        return INSTANCE.getConnection();
    }
    public static Table getTable(String tableName) throws IOException {
        return INSTANCE.getConnection().getTable(TableName.valueOf(tableName));
    }
    public static void closeConn(){
        if (connection!=null){
            try {
                connection.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

3.具体操作hbase 工具类

package com.zsk.hbase.api;

import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.util.Bytes;

import java.util.Arrays;
import java.util.List;

public class HBaseUtil {
    /**
     * 创建表
     * @param tableName 创建表的表名称
     * @param cfs 列簇的集合
     * @return
     */
    public static boolean createTable(String tableName, String[] cfs) {
        try (HBaseAdmin admin = (HBaseAdmin) HBaseConn.getHBaseConn().getAdmin()) {
            if (admin.tableExists(tableName)) {
                return false;
            }
            HTableDescriptor tableDescriptor = new HTableDescriptor(TableName.valueOf(tableName));
            Arrays.stream(cfs).forEach(cf -> {
                HColumnDescriptor columnDescriptor = new HColumnDescriptor(cf);
                columnDescriptor.setMaxVersions(1);
                tableDescriptor.addFamily(columnDescriptor);
            });
            admin.createTable(tableDescriptor);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return true;
    }

    /**
     * 删除表
     * @param tableName 表名称
     * @return
     */
    public static boolean deleteTable(String tableName){
        try(HBaseAdmin admin = (HBaseAdmin)HBaseConn.getHBaseConn().getAdmin()){
            if (!admin.tableExists(tableName)){
                return false;
            }
            admin.disableTable(tableName);
            admin.deleteTable(tableName);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }

    /**
     * 插入数据
     * @param tableName
     * @param rowkey
     * @param cfName
     * @param qualifer
     * @param data
     * @return
     */
    public static boolean putRow(String tableName,String rowkey,String cfName,String qualifer,String data){
        try(Table table = HBaseConn.getTable(tableName)){
            Put put = new Put(Bytes.toBytes(rowkey));
            put.addColumn(Bytes.toBytes(cfName),Bytes.toBytes(qualifer),Bytes.toBytes(data));
            table.put(put);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }

    /**
     *批量出入数据
     * @param tableName
     * @param puts
     * @return
     */
    public static boolean putRows(String tableName, List<Put> puts){
        try(Table table = HBaseConn.getTable(tableName)){
            table.put(puts);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }

    /**
     * 查询单条数据
     * @param tableName
     * @param rowkey
     * @return
     */
    public static Result getRow(String tableName,String rowkey){
        try( Table table = HBaseConn.getTable(tableName)){
            Get get = new Get(Bytes.toBytes(rowkey));
            return table.get(get);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 带有过滤器的插入数据
     * @param tableName
     * @param rowkey
     * @param filterList
     * @return
     */
    public static Result getRow(String tableName, String rowkey, FilterList filterList){
        try( Table table = HBaseConn.getTable(tableName)){
            Get get = new Get(Bytes.toBytes(rowkey));
            get.setFilter(filterList);
            Result result = table.get(get);
            System.out.println("rowkey == "+Bytes.toString(result.getRow()));
            System.out.println("basic:name == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("name"))));
            System.out.println("basic:age == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("age"))));
            System.out.println("basic:sex == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("sex"))));
            System.out.println("basic:salary == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("salary"))));
            System.out.println("basic:job == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("job"))));
            return result;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    /**
     *scan扫描数据，
     * @param tableName
     * @return
     */
    public static ResultScanner getScanner(String tableName){
        try( Table table = HBaseConn.getTable(tableName)){
            Scan scan = new Scan();
            scan.setCaching(1000);
            ResultScanner results = table.getScanner(scan);
            results.forEach(result -> {
                System.out.println("rowkey == "+Bytes.toString(result.getRow()));
                System.out.println("basic:name == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("name"))));
                System.out.println("basic:age == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("age"))));
                System.out.println("basic:sex == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("sex"))));
                System.out.println("basic:salary == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("salary"))));
                System.out.println("basic:job == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("job"))));
            });
            return results;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    /**
     *can 检索数据，控制startrow，stoprow 注意包括startrow 不包括stoprow，
     * @param tableName
     * @param startKey
     * @param stopKey
     * @return
     */
    public static ResultScanner getScanner(String tableName,String startKey,String stopKey){
        try( Table table = HBaseConn.getTable(tableName)){
            Scan scan = new Scan();
            scan.setStartRow(Bytes.toBytes(startKey));
            scan.setStopRow(Bytes.toBytes(stopKey));
            scan.setCaching(1000);
            ResultScanner results = table.getScanner(scan);
            results.forEach(result -> {
                System.out.println("rowkey == "+Bytes.toString(result.getRow()));
                System.out.println("basic:name == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("name"))));
                System.out.println("basic:age == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("age"))));
                System.out.println("basic:sex == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("sex"))));
                System.out.println("basic:salary == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("salary"))));
                System.out.println("basic:job == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("job"))));
            });
            return results;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    /**
     * scan 检索数据，控制startrow，stoprow 注意包括startrow 不包括stoprow，filterList对查询过滤
     * @param tableName
     * @param startKey
     * @param stopKey
     * @param filterList
     * @return
     */
    public static ResultScanner getScanner(String tableName,String startKey,String stopKey,FilterList filterList){
        try( Table table = HBaseConn.getTable(tableName)){
            Scan scan = new Scan();
            scan.setFilter(filterList);
            scan.setStartRow(Bytes.toBytes(startKey));
            scan.setStopRow(Bytes.toBytes(stopKey));
            scan.setCaching(1000);
            ResultScanner results = table.getScanner(scan);
            results.forEach(result -> {
                System.out.println("rowkey == "+Bytes.toString(result.getRow()));
                System.out.println("basic:name == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("name"))));
                System.out.println("basic:age == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("age"))));
                System.out.println("basic:sex == "+Bytes.toString(result.getValue(Bytes.toBytes("basic"), Bytes.toBytes("sex"))));
                System.out.println("basic:salary == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("salary"))));
                System.out.println("basic:job == "+Bytes.toString(result.getValue(Bytes.toBytes("extend"), Bytes.toBytes("job"))));
            });
            return results;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 删除行
     * @param tableName
     * @param rowkey
     * @return
     */
    public static boolean deleteRow(String tableName,String rowkey){
        try( Table table = HBaseConn.getTable(tableName)){
            Delete delete = new Delete(Bytes.toBytes(rowkey));
            table.delete(delete);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }

    /**
     *删除列簇
     * @param tableName
     * @param cfName
     * @return
     */
    public static boolean deleteColumnFamily(String tableName,String cfName){
        try(HBaseAdmin admin = (HBaseAdmin)HBaseConn.getHBaseConn().getAdmin()){
            admin.deleteColumn(tableName,cfName);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }
    /**
     * 删除列
     * @param tableName
     * @param cfName
     * @return
    */
    public static boolean deleteQualifier(String tableName,String rowkey,String cfName,String qualiferName){
        try(Table table = HBaseConn.getTable(tableName)){
            Delete delete = new Delete(Bytes.toBytes(rowkey));
            delete.addColumn(Bytes.toBytes(cfName),Bytes.toBytes(qualiferName));
            table.delete(delete);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }
}

总结：

• hbase 数据类型只有bytes类型，而关系型数据库 可以有多种多样的数据类型。所以我们根据rowkey，cf，qualifer等条件进行查询的时候，需要将对应的字段通过Bytes.toBytes（）方法进行封装。同样，对于返回的result，也需要通过Bytes.toString（）方法转为string对象。

• hbase 不支持更新操作，要实现更新操作，只能够先删除该数据 然后重新插入。

• 我们可以看到某些情况下只需要Table实例，即可实现响应操作，但是某些情况需要HBaseAdmin实例，才能进行修改，删除等操作。具体什么时候，使用那种操作呢？通过前面文章HBase读写流程https://blog.csdn.net/zhangshk_/article/details/83663642应该不难明白。对于修改删除列簇，还有涉及表的创建删除等操作，是需要HBaseAdmin操作的，因为这些操作需要涉及meta表的更新。而其他的操作，只需要通过zookeeper获取数据的regionserver，通过regionserver就可完成读写请求。