什么是Thrift？

Thrift是一种RPC（远程过程调用）软件框架，用来进行可扩展且跨语言的服务的开发。它结合了功能强大的软件堆栈和代码生成引擎，以构建在 C++, Java, Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, java script, Node.js, Smalltalk, and OCaml 这些编程语言间无缝结合的、高效的服务。

C#通过Thrift访问HBase

• HBase提供了Thrift服务端
• C#可执行程序可创建Thrift客户端连接到HBase。

---

准备

下载Thrift

编译器：Thrift compiler for Windows (thrift-0.9.3.exe)
源代码及驱动库：thrift-0.9.3.tar.gz

下载HBase安装包

HBase-1.2.2-bin.tar.gz

生成C#的Thrift客户端

1.创建一个文件夹用于存放所有的材料，本文示例：workspace

2.解压thrift-0.9.3.tar.gz，复制lib/csharp中找到workspace。根据需要修改.Net framework 3.5到 4.0或以上，并编译得到Thrift.dll。

3.创建测试项目HBaseTest，并引用Thrift.dll。

4.解压HBase的安装包，从安装包中复制HBase.thrift文件到workspace。

\hbase-1.2.2\hbase-thrift\src\main\resources\org\apache\hadoop\hbase\thrift\hbase.thrift

注意： HBase有两个版本的thrift，分别是thrift和thrift2。我们这里讲解的是的thrift。

5.启用cmd命令行模式，进入workspace，执行以下命令生成代码：

thrift-0.9.3.exe -gen csharp hbase.thrift

执行后会生成gen-csharp目录，里面包含了HBase的Thrift客户端代码。

6.将生成的代码加入到HBaseTest项目中。

---

开发

AbstractHBaseThriftService 抽象服务

这里，我们实际上是对HBase Thrift客户端Java API实践中的Java代码进行了翻译，改写成C#语言的相关操作。我们在客户端，进行了一层抽象，更加便于传递各种参数，抽象类为AbstractHBaseThriftService，该类实现代码如下所示：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Thrift.Transport;
using Thrift.Protocol;

namespace HBaseTest
{
    /// <summary>
    /// HBaseThrift客户端抽象服务
    /// </summary>
    public abstract class AbstractHBaseThriftService
    {
        protected static readonly string CHARSET = "UTF-8";
        private string host = "localhost";
        private int port = 9090;
        private readonly TTransport transport;
        protected readonly Hbase.Client client;

        public AbstractHBaseThriftService() : 
            this("localhost", 9090)
        {

        }

        public AbstractHBaseThriftService(string host, int port)
        {
            this.host = host;
            this.port = port;
            transport = new TSocket(host, port);
            TProtocol protocol = new TBinaryProtocol(transport, true, true);
            client = new Hbase.Client(protocol);
        }

        /// <summary>
        /// 打开通讯通道
        /// </summary>
        public void Open()
        {
            if (transport != null)
            {
                transport.Open();
            }
        }

        /// <summary>
        /// 关闭通讯通道
        /// </summary>
        public void Close()
        {
            if (transport != null)
            {
                transport.Close();
            }
        }

        /// <summary>
        /// 获取HBase数据所有用户表
        /// </summary>
        /// <returns></returns>
        public abstract List<string> GetTables();

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <param name="table"></param>
        /// <param name="rowKey"></param>
        /// <param name="writeToWal"></param>
        /// <param name="fieldName"></param>
        /// <param name="fieldValue"></param>
        /// <param name="attributes"></param>
        public abstract void Update(
            string table, 
            string rowKey, 
            bool writeToWal,
            string fieldName, 
            string fieldValue, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="rowKey"></param>
        /// <param name="writeToWal"></param>
        /// <param name="fieldNameva lues"></param>
        /// <param name="attributes"></param>
        public abstract void Update(
            string table,
            string rowKey, 
            bool writeToWal,
            Dictionary<string, string> fieldNameva lues, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 删除表中单元格
        /// </summary>
        /// <param name="table">表名</param>
        /// <param name="rowKey">行健</param>
        /// <param name="writeToWal"></param>
        /// <param name="column">列族</param>
        /// <param name="attributes">属性</param>
        public abstract void DeleteCell(
            string table,
            string rowKey, 
            bool writeToWal,
            string column, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 删除表中指定单元格
        /// </summary>
        /// <param name="table">表名</param>
        /// <param name="rowKey">行健</param>
        /// <param name="writeToWal"></param>
        /// <param name="columns">列族</param>
        /// <param name="attributes">属性</param>
        public abstract void DeleteCells(
            string table, 
            string rowKey, 
            bool writeToWal,
            List<string> columns, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 删除行
        /// </summary>
        /// <param name="table">表名</param>
        /// <param name="rowKey">行健</param>
        /// <param name="attributes">属性</param>
        public abstract void DeleteRow(
            string table, 
            string rowKey,
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="startRow"></param>
        /// <param name="columns"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract int ScannerOpen(
            string table, 
            string startRow,
            List<string> columns,
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="startRow"></param>
        /// <param name="stopRow"></param>
        /// <param name="columns"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract int ScannerOpen(
            string table, 
            string startRow, 
            string stopRow, 
            List<string> columns,
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="startAndPrefix"></param>
        /// <param name="columns"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract int ScannerOpenWithPrefix(
            string table, 
            string startAndPrefix,
            List<string> columns, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="startRow"></param>
        /// <param name="columns"></param>
        /// <param name="timestamp"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract int ScannerOpenTs(
            string table, 
            string startRow,
            List<string> columns, 
            long timestamp, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="table"></param>
        /// <param name="startRow"></param>
        /// <param name="stopRow"></param>
        /// <param name="columns"></param>
        /// <param name="timestamp"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract int ScannerOpenTs(
            string table, 
            string startRow, 
            string stopRow,
            List<string> columns, 
            long timestamp, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 扫描器获取行列表
        /// </summary>
        /// <param name="id"></param>
        /// <param name="nbRows"></param>
        /// <returns></returns>
        public abstract List<TRowResult> ScannerGetList(int id, int nbRows);

        /// <summary>
        /// 扫描器获取行数据
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public abstract List<TRowResult> ScannerGet(int id);

        /// <summary>
        /// 获取指定行
        /// </summary>
        /// <param name="table"></param>
        /// <param name="row"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract List<TRowResult> GetRow(
            string table, 
            string row,
            Dictionary<string, string> attributes);

        /// <summary>
        /// 批量获取列族
        /// </summary>
        /// <param name="table"></param>
        /// <param name="rows"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract List<TRowResult> GetRows(
            string table,
            List<string> rows, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 批量获取指定列族的行
        /// </summary>
        /// <param name="table"></param>
        /// <param name="rows"></param>
        /// <param name="columns"></param>
        /// <param name="attributes"></param>
        /// <returns></returns>
        public abstract List<TRowResult> GetRowsWithColumns(
            string table,
            List<string> rows, 
            List<string> columns, 
            Dictionary<string, string> attributes);

        /// <summary>
        /// 关闭扫描器
        /// </summary>
        /// <param name="id"></param>
        public abstract void ScannerClose(int id);

        /// <summary>
        /// 迭代结果
        /// </summary>
        /// <param name="result"></param>
        public abstract void IterateResults(TRowResult result);

    }
}

Thrift服务的基本功能

• 建立到Thrift服务的连接：Open()
• 获取到HBase中的所有表名：GetTables()
• 更新HBase表记录：Update()
• 删除HBase表中一行的记录的数据（cell）：DeleteCell()和DeleCells()
• 删除HBase表中一行记录：deleteRow()
• 打开一个Scanner，返回id：ScannerOpen()、ScannerOpenWithPrefix()和ScannerOpenTs()；然后用返回的id迭代记录：ScannerGetList()和ScannerGet()
• 获取一行记录结果：GetRow()、GetRows()和GetRowsWithColumns()
• 关闭一个Scanner：ScannerClose()
• 迭代结果，用于调试：IterateResults()

HBaseThriftService 抽象服务

根据抽象HBaseThrift抽象服务定义，我们的一个实现如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HBaseTest
{
    /// <summary>
    /// HBaseThrift服务
    /// </summary>
    public class HBaseThriftService : AbstractHBaseThriftService
    {
        public HBaseThriftService() 
            : this("localhost", 9090)
        {

        }

        public HBaseThriftService(string host, int port) 
            : base(host, port)
        {

        }

        /// <inheriated-doc />
        public override List<string> GetTables()
        {
            List<byte[]> tables = client.getTableNames();
            List<String> list = new List<String>();
            foreach (byte[] table in tables)
            {
                list.Add(Decode(table));
            }
            return list;
        }

        /// <inheriated-doc />
        public override void Update(string table, string rowKey, bool writeToWal, string fieldName, string fieldValue, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] row = Encode(rowKey);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            List<Mutation> mutations = new List<Mutation>();
            Mutation mutation = new Mutation();
            mutation.IsDelete = false;
            mutation.WriteToWAL = writeToWal;
            mutation.Column = Encode(fieldName);
            mutation.Value = Encode(fieldValue);
            mutations.Add(mutation);
            client.mutateRow(tableName, row, mutations, encodedAttributes);
        }

        /// <inheriated-doc />
        public override void Update(string table, string rowKey, bool writeToWal, Dictionary<string, string> fieldNameva lues, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] row = Encode(rowKey);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            List<Mutation> mutations = new List<Mutation>();
            foreach (KeyValuePair<String, String> pair in fieldNameva lues)
            {
                Mutation mutation = new Mutation();
                mutation.IsDelete = false;
                mutation.WriteToWAL = writeToWal;
                mutation.Column = Encode(pair.Key);
                mutation.Value = Encode(pair.Value);
                mutations.Add(mutation);
            }
            client.mutateRow(tableName, row, mutations, encodedAttributes);
        }

        /// <inheriated-doc />
        public override void DeleteCell(string table, string rowKey, bool writeToWal, string column, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] row = Encode(rowKey);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            List<Mutation> mutations = new List<Mutation>();
            Mutation mutation = new Mutation();
            mutation.IsDelete = true;
            mutation.WriteToWAL = writeToWal;
            mutation.Column = Encode(column);
            mutations.Add(mutation);
            client.mutateRow(tableName, row, mutations, encodedAttributes);
        }

        /// <inheriated-doc />
        public override void DeleteCells(string table, string rowKey, bool writeToWal, List<string> columns, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] row = Encode(rowKey);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            List<Mutation> mutations = new List<Mutation>();
            foreach (string column in columns)
            {
                Mutation mutation = new Mutation();
                mutation.IsDelete = true;
                mutation.WriteToWAL = writeToWal;
                mutation.Column = Encode(column);
                mutations.Add(mutation);
            }
            client.mutateRow(tableName, row, mutations, encodedAttributes);
        }

        /// <inheriated-doc />
        public override void DeleteRow(string table, string rowKey, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] row = Encode(rowKey);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            client.deleteAllRow(tableName, row, encodedAttributes);
        }

        /// <inheriated-doc />
        public override int ScannerOpen(string table, string startRow, List<string> columns, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] start = Encode(startRow);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.scannerOpen(tableName, start, encodedColumns, encodedAttributes);
        }

        /// <inheriated-doc />
        public override int ScannerOpen(string table, string startRow, string stopRow, List<string> columns, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] start = Encode(startRow);
            byte[] stop = Encode(stopRow);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.scannerOpenWithStop(tableName, start, stop, encodedColumns, encodedAttributes);
        }

        /// <inheriated-doc />
        public override int ScannerOpenWithPrefix(string table, string startAndPrefix, List<string> columns, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] prefix = Encode(startAndPrefix);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.scannerOpenWithPrefix(tableName, prefix, encodedColumns, encodedAttributes);
        }

        /// <inheriated-doc />
        public override int ScannerOpenTs(string table, string startRow, List<string> columns, long timestamp, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] start = Encode(startRow);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.scannerOpenTs(tableName, start, encodedColumns, timestamp, encodedAttributes);
        }

        /// <inheriated-doc />
        public override int ScannerOpenTs(string table, string startRow, string stopRow, List<string> columns, long timestamp, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] start = Encode(startRow);
            byte[] stop = Encode(stopRow);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.scannerOpenWithStopTs(tableName, start, stop, encodedColumns, timestamp, encodedAttributes);
        }

        /// <inheriated-doc />
        public override List<TRowResult> ScannerGetList(int id, int nbRows)
        {
            return client.scannerGetList(id, nbRows);
        }

        /// <inheriated-doc />
        public override List<TRowResult> ScannerGet(int id)
        {
            return client.scannerGet(id);
        }

        /// <inheriated-doc />
        public override List<TRowResult> GetRow(string table, string row, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            byte[] startRow = Encode(row);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.getRow(tableName, startRow, encodedAttributes);
        }

        /// <inheriated-doc />
        public override List<TRowResult> GetRows(string table, List<string> rows, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            List<byte[]> encodedRows = EncodeStringList(rows);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.getRows(tableName, encodedRows, encodedAttributes);
        }

        /// <inheriated-doc />
        public override List<TRowResult> GetRowsWithColumns(string table, List<string> rows, List<string> columns, Dictionary<string, string> attributes)
        {
            byte[] tableName = Encode(table);
            List<byte[]> encodedRows = EncodeStringList(rows);
            List<byte[]> encodedColumns = EncodeStringList(columns);
            Dictionary<byte[], byte[]> encodedAttributes = EncodeAttributes(attributes);
            return client.getRowsWithColumns(tableName, encodedRows, encodedColumns, encodedAttributes);
        }

        /// <inheriated-doc />
        public override void ScannerClose(int id)
        {
            client.scannerClose(id);
        }

        /// <inheriated-doc />
        public override void IterateResults(TRowResult result)
        {
            foreach (KeyValuePair<byte[], TCell> pair in result.Columns)
            {
                Console.WriteLine("\tCol=" + Decode(pair.Key) + ", Value=" + Decode(pair.Value.Value));
            }
        }

        /// <inheriated-doc />
        private String Decode(byte[] bs)
        {
            return UTF8Encoding.Default.GetString(bs);
        }

        /// <inheriated-doc />
        private byte[] Encode(String str)
        {
            return UTF8Encoding.Default.GetBytes(str);
        }

        /// <inheriated-doc />
        private Dictionary<byte[], byte[]> EncodeAttributes(Dictionary<String, String> attributes)
        {
            Dictionary<byte[], byte[]> encodedAttributes = new Dictionary<byte[], byte[]>();
            foreach (KeyValuePair<String, String> pair in attributes)
            {
                encodedAttributes.Add(Encode(pair.Key), Encode(pair.Value));
            }
            return encodedAttributes;
        }

        /// <inheriated-doc />
        private List<byte[]> EncodeStringList(List<String> strings)
        {
            List<byte[]> list = new List<byte[]>();
            if (strings != null)
            {
                foreach (String str in strings)
                {
                    list.Add(Encode(str));
                }
            }
            return list;
        }
    }
}

HBaseThrift 测试用例

针对HBase的Thrift接口，我们做了测试用例如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HBaseTest
{
    class Test
    {
        private readonly AbstractHBaseThriftService thriftService;

        public Test(String host, int port)
        {
            thriftService = new HBaseThriftService(host, port);
            thriftService.Open();
        }

        public Test() : this("master", 9090)
        {

        }

        static String RandomlyBirthday()
        {
            Random r = new Random();
            int year = 1900 + r.Next(100);
            int month = 1 + r.Next(12);
            int date = 1 + r.Next(30);
            return year + "-" + month.ToString().PadLeft(2, '0') + "-" + date.ToString().PadLeft(2, '0');
        }

        static String RandomlyGender()
        {
            Random r = new Random();
            int flag = r.Next(2);
            return flag == 0  "M" : "F";
        }

        static String RandomlyUserType()
        {
            Random r = new Random();
            int flag = 1 + r.Next(10);
            return flag.ToString();
        }

        public void Close()
        {
            thriftService.Close();
        }


        public void CaseForGetTables()
        {
            var tableNameList = thriftService.GetTables();
            foreach (var existedTableName in tableNameList)
            {
                Console.WriteLine("Table:{0}", existedTableName);
            }
        }

        public void CaseForCreateTable(
            string tableName,
            IList<string> columnNameList)
        {
            thriftService.CreateTable(tableName, columnNameList);
        }

        public void CaseForUpdate()
        {
            bool writeToWal = false;
            Dictionary<String, String> attributes = new Dictionary<String, String>(0);
            string table = SetTable();
            // put kv pairs

            System.Diagnostics.Stopwatch watch = new System.Diagnostics.Stopwatch();
            watch.Start();
            for (long i = 0; i < 50000; i++)
            {
                string rowKey = i.ToString().PadLeft(4, '0');
                Dictionary<String, String> fieldNameva lues = new Dictionary<String, String>();
                fieldNameva lues.Add("info:name", RandomNameGen.getRandomName());
                fieldNameva lues.Add("info:birthday", RandomlyBirthday());
                fieldNameva lues.Add("info:user_type", RandomlyUserType());
                fieldNameva lues.Add("info:gender", RandomlyGender());
                thriftService.Update(table, rowKey, writeToWal, fieldNameva lues, attributes);

                if (i % 10000 == 0)
                {
                    Console.WriteLine(
                        "Insert [{0}] Rows Time Eclipsed:{1}",
                        i,
                        watch.ElapsedMilliseconds);
                }
            }
            watch.Stop();

            Console.WriteLine(
                        "Insert [{0}] Rows Time Eclipsed:{1}",
                        50000,
                        watch.ElapsedMilliseconds);
        }

        public void CaseForDeleteCells()
        {
            bool writeToWal = false;
            Dictionary<String, String> attributes = new Dictionary<String, String>(0);
            String table = SetTable();
            // put kv pairs
            for (long i = 5; i < 10; i++)
            {
                String rowKey = i.ToString().PadLeft(4, '0');
                List<String> columns = new List<String>(0);
                columns.Add("info:birthday");
                thriftService.DeleteCells(table, rowKey, writeToWal, columns, attributes);
            }
        }

        public void CaseForDeleteRow()
        {
            Dictionary<String, String> attributes = new Dictionary<String, String>(0);
            String table = SetTable();
            // delete rows
            for (long i = 5; i < 10; i++)
            {
                String rowKey = i.ToString().PadLeft(4, '0');
                thriftService.DeleteRow(table, rowKey, attributes);
            }
        }

        public void CaseForScan()
        {
            Dictionary<String, String> attributes = new Dictionary<String, String>(0);
            String table = SetTable();
            String startRow = "0001";
            String stopRow = "0015";
            List<String> columns = new List<String>(0);
            columns.Add("info:name");
            int id = thriftService.ScannerOpen(table, startRow, stopRow, columns, attributes);
            int nbRows = 2;
            List<TRowResult> results = thriftService.ScannerGetList(id, nbRows);
            while (results.Count > 0)
            {
                foreach (TRowResult result in results)
                {
                    thriftService.IterateResults(result);
                }
                results = thriftService.ScannerGetList(id, nbRows);
            }
            thriftService.ScannerClose(id);
        }

        public void CaseForGet()
        {
            Dictionary<String, String> attributes = new Dictionary<String, String>(0);
            String table = SetTable();
            List<String> rows = new List<String>(0);
            rows.Add("0009");
            rows.Add("0098");
            rows.Add("0999");
            List<String> columns = new List<String>(0);
            columns.Add("info:birthday");
            columns.Add("info:gender");
            List<TRowResult> results = thriftService.GetRowsWithColumns(table, rows, columns, attributes);
            foreach (TRowResult result in results)
            {
                thriftService.IterateResults(result);
            }
        }

        private string SetTable()
        {
            string table = "test-user";
            return table;
        }
    }
}

Program 控制台程序启动类

准备好测试用例后，控制台程序的入口处调用即可：

using System;
using System.Diagnostics;
using System.IO;
using System.Text;

namespace HBaseTest
{
    class Program
    {
        static void Main(string[] args)
        {
            Test test = new Test();
            test.CaseForGetTables();
            test.CaseForCreateTable("test-user",new[] { "info" });
            test.CaseForGetTables();
            test.CaseForUpdate();
            test.CaseForGet();
            test.CaseForScan();
            test.CaseForDeleteCells();
            test.CaseForDeleteRow();
            Console.ReadLine();
        }
    }
}

附A: Thrift2

thrift和thrift2有很大的差别，tthrift2做了简化与合成，并把DDL有关的内容去掉了。未来thrift将被抛弃，固在后续文章中介绍thrift2的使用。

附B: HBase实现分页步骤

HBase实现分页的逻辑和传统的关系型数据库操作有些不同。其常用步骤如下：

1. 打开一个Scanner实例（例如调用ScannerOpen()），返回一个id
2. 使用该id调用ScannerGetList()方法（可以指定每次返回几条记录的变量nbRows的值），返回一个记录列表。
3. 反复调用该ScannerGetList()方法，直到此次没有结果返回为止。