數據字典生成工具之旅(9)：多線程使用及介紹

時間  2019-11-21
標籤 數據 字典 生成 工具 之旅 多線程 使用 介紹 欄目 Java 简体版
原文   原文鏈接

      這一篇將在以前的代碼生成器上講解多線程的應用，多線程的概念和好處這裏就很少說了，另外從本篇開始後面的實例代碼都將放到淘寶的SVN管理工具上維護，你們能夠直接使用SVN工具進行下載。好了下面進入本篇內容。html

閱讀目錄數據庫

線程的應用

     這裏先講一下線程在Web程序中的一個應用，以前的那一版代碼生成器沒有考慮表數量多的情形，這裏先模擬一下在數據庫中建立300張表的情形，下面給出建立表的語句 。安全

--模擬建立300張表，@IsDropTable=0 表示建立表 IsDropTable=1 表示刪除建立的模擬表
DECLARE @IsDropTable AS BIT
DECLARE @total AS INT 
DECLARE @i AS INT
SELECT @i=1,@total=300,@IsDropTable=0
WHILE @i<=@total
BEGIN
DECLARE @strSQL AS VARCHAR(1000)
    --建立表
    SELECT @strSQL='
        CREATE TABLE myTest'+CONVERT(VARCHAR,@i)+'
        (
            [UserGUID] [uniqueidentifier] NOT NULL
        )
        EXEC sp_addextendedproperty N''MS_Description'', N''用戶表'', ''SCHEMA'', N''dbo'', ''TABLE'', N''myTest'+CONVERT(VARCHAR,@i)+''', NULL, NULL
        EXEC sp_addextendedproperty N''MS_Description'', N''用戶GUID'', ''SCHEMA'', N''dbo'', ''TABLE'', N''myTest'+CONVERT(VARCHAR,@i)+''', ''COLUMN'', N''UserGUID''
    '    
    IF @IsDropTable=1
    BEGIN
        --刪除表
        SELECT @strSQL='DROP TABLE myTest'+CONVERT(VARCHAR,@i)
    END
    
    EXEC(@strSQL)
    SELECT @i=@i+1
END
View Code

    咱們來看下執行時間，差很少用了22秒，時間仍是挺長的。能夠將代碼改造一下，使用多線程來生成代碼。多線程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Configuration;
using System.Collections;
using System.IO;
using System.Data;
using System.Threading;

namespace Mysoft.Code.Services
{
    /// <summary>
    /// 代碼生成類
    /// </summary>
    public class CodeGenerator
    {
        //模版文件路徑
        private static string tmpPath = HttpContext.Current.Server.MapPath("/實體模版/Entity.vm");

        //模版輸出路徑
        private static string outPutPath = HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["outputPath"]);


        private static readonly int Number10 = 400;
        private static readonly int MaxThreadCount = 4;

        /// <summary>
        /// 批量生成代碼
        /// </summary>
        /// <param name="args">模版文件參數</param>
        public static void BatchGenerator(List<Hashtable> args)
        {
            if (!Directory.Exists(outPutPath))
            {
                Directory.CreateDirectory(outPutPath);
            }
            //生成文件數量<Number10，則不開啓線程生成
            if (args.Count < Number10)
            {
                DoWork(args);
            }
            else
            {
                //計算須要的線程數
                int threadCount = args.Count % Number10 == 0 ? args.Count / Number10 : args.Count / Number10 + 1;
                if (threadCount > MaxThreadCount)
                {
                    threadCount = MaxThreadCount;
                }

                //每一個線程須要生成的實體數量
                int threadPqgeSize = (args.Count / threadCount) + 1;
                int total = 0;
                //爲每一個線程準備參數
                List<List<Hashtable>> threadParams = new List<List<Hashtable>>();
                for (int i = 0; i < threadCount; i++)
                {
                    threadParams.Add(args.Skip(total).Take(threadPqgeSize).ToList());
                    total += threadParams[i].Count;
                }
                //建立線程
                List<Thread> threads = new List<Thread>();
                for (int i = 1; i < threadCount; i++)
                {
                    Thread thread = new Thread(DoWork);
                    thread.IsBackground = true;
                    thread.Name = "CodeGenerator #" + i.ToString();
                    threads.Add(thread);
                    thread.Start(threadParams[i]);
                }

                // 爲當前線程指派生成任務。
                DoWork(threadParams[0]);


                // 等待全部的編譯線程執行線束。
                foreach (Thread thread in threads)
                {
                    thread.Join();
                }
            }
        }

        private static void DoWork(Object listArgs)
        {
            List<Hashtable> list = (List<Hashtable>)listArgs;
            foreach (Hashtable ht in list)
            {
                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, ((DataTable)ht["T"]).Rows[0]["table_name"].ToString()));
            }
        }

    }
}
View Code

    代碼思路，判斷要生成的實體數量和Number10的關係，而後計算所需的線程數。ide

   關鍵的一點是 thread.Join()，這段是主線程等待每一個線程執行完成。如今再來看下執行時間，差很少用了13秒，節省了將近10S的時間。svn

 

 

winform程序中的多線程

    下面來考慮這樣的一個場景，在生成了文件的時候立刻在列表中提示實體生成完成，即進度提示的功能。咱們來看下winform中的兩種實現方式。工具

    1.利用委託實現學習

     先看一下普通線程實現方式，執行的時候會拋出以下異常。ui

   foreach (var key in query)
            {
                dv.RowFilter = "tableid=" + key.tableid;
                DataTable dtTable = dv.ToTable();
                Hashtable ht = new Hashtable();
                ht["T"] = dtTable;
                string tableName = dtTable.Rows[0]["table_name"].ToString();
                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, tableName));
                Thread thread = new Thread(BindMessage);
                thread.IsBackground = true;
                thread.Name = "BindMessage:" + key.tableid;
                thread.Start(tableName);
            }
View Code

     先看一下msdn的介紹：this

       訪問 Windows 窗體控件本質上不是線程安全的。若是有兩個或多個線程操做某一控件的狀態，則可能會迫使該控件進入一種不一致的狀態。還可能出現其餘與線程相關的 bug，包括爭用狀況和死鎖。確保以線程安全方式訪問控件很是重要。

　　C#中禁止跨線程直接訪問控件，InvokeRequired是爲了解決這個問題而產生的，當一個控件的InvokeRequired屬性值爲真時，說明有一個建立它之外的線程想訪問它。

      因而改變了思路，新建線程用以執行耗時的生成代碼操做，在每生成一個實體時，通知UI線程更新dataGridView，達到實時更新的效果,這樣主線程也不會阻塞了。

   

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Mysoft.Map.Extensions.DAL;
using System.Collections;
using Mysoft.Code.Services;
using System.IO;
using System.Threading;

namespace ThreadWin
{
    public partial class MainForm : Form
    {
        //模版文件路徑
        private static string tmpPath = AppDomain.CurrentDomain.BaseDirectory + @"實體模版\Entity.vm";

        //模版輸出路徑
        private static string outPutPath = AppDomain.CurrentDomain.BaseDirectory + @"模版輸出路徑";

        private DataTable dtInfo = new DataTable();

        /// <summary>
        /// 消息發送請求委託
        /// </summary>
        /// <param name="Msg">消息</param>
        delegate void SetMessageCallBack(object Msg);

        public MainForm()
        {
            InitializeComponent();
            dtInfo.Columns.Add("TableName");
            dtInfo.Columns.Add("Info");
            dtInfo.Columns.Add("Time");
            Control.CheckForIllegalCrossThreadCalls = false;
        }

        private void btn_OK_Click(object sender, EventArgs e)
        {
            dtInfo.Clear();
            

            if (!Directory.Exists(outPutPath))
            {
                Directory.CreateDirectory(outPutPath);
            }
            //1.耗時的操做放在新建線程裏面執行
            Thread thread = new Thread(GeneratorFile);
            thread.IsBackground = true;
            thread.Start();

            //2.使用系統的線程池進行線程操做
            //ThreadPool.QueueUserWorkItem(GeneratorFile);
        }

        /// <summary>
        /// 這裏進行耗時的生成代碼操做
        /// </summary>
        private void GeneratorFile()
        {
            //循環生成實體，而且在列表上顯示進度
            DataTable dt = GetAllTableInfo();
            DataView dv = dt.DefaultView;
            var query = (from p in dt.AsEnumerable()
                         group p by new { TableId = p.Field<int>("tableid"), TableName = p.Field<string>("table_name") } into q
                         select new { TableId = q.Key.TableId, TableName = q.Key.TableName }
                        );
            foreach (var key in query)
            {
                dv.RowFilter = "tableid=" + key.TableId;
                DataTable dtTable = dv.ToTable();
                Hashtable ht = new Hashtable();
                ht["T"] = dtTable;
                string tableName = dtTable.Rows[0]["table_name"].ToString();
                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, key.TableName));

                //消息提示
                DataRow dr = dtInfo.NewRow();
                dr["TableName"] = tableName;
                dr["Info"] = "生成成功";
                dr["Time"] = DateTime.Now.ToString();
                dtInfo.Rows.Add(dr);
                DataView dvOrder = dtInfo.DefaultView;
                dvOrder.Sort = "Time DESC";
                DataTable dtinfo = dvOrder.ToTable();
                if (this.dataGridView.InvokeRequired)
                {
                    SetMessageCallBack stms = new SetMessageCallBack(BindMessage);
                    if (this != null)
                    {
                        this.Invoke(stms, new object[] { dtinfo });
                    }
                }
                else
                {
                    dataGridView.DataSource = dvOrder.ToTable();
                }
            }

            
        }

        /// <summary>
        /// 列表顯示最新消息
        /// </summary>
        /// <param name="dt"></param>
        private void BindMessage(object dt)
        {
            dataGridView.DataSource = dt;
        }

        /// <summary>
        /// 獲取全部表信息
        /// </summary>
        /// <returns></returns>
        public DataTable GetAllTableInfo()
        {
            string strSQL = @"    SELECT T.name AS table_name ,
            T.object_id AS tableid,
            ISNULL(CONVERT(VARCHAR(MAX), E.value), '') AS table_name_c ,
            C.name AS field_name ,
            ISNULL(CONVERT(VARCHAR(MAX), D.value), '') AS field_name_c ,
            ROW_NUMBER() OVER(PARTITION BY T.name ORDER BY C.colid) AS field_sequence ,
            TYPE_NAME(C.xtype) AS date_type ,
            (CASE WHEN EXISTS ( SELECT   1
            FROM     sysobjects
            WHERE    xtype = 'PK'
            AND name IN (
            SELECT  name
            FROM    sysindexes
            WHERE   id = C.id
            AND indid IN (
            SELECT  indid
            FROM    sysindexkeys
            WHERE   id = C.id
            AND colid = C.colid ) ) )
            THEN 1
            ELSE 0
            END) AS pk ,
            ISNULL(C.isnullable, 1) AS isnullable ,
            ISNULL(COLUMNPROPERTY(c.id, c.name, 'IsIdentity'), 0) AS isidentity
            FROM   sys.tables AS T
            LEFT JOIN syscolumns AS C ON c.id = T.object_id
            LEFT JOIN sys.extended_properties AS D ON D.major_id = T.object_id
            AND D.minor_id = C.colid
            AND D.major_id = C.id
            LEFT JOIN sys.extended_properties AS E ON E.major_id = T.object_id
            AND E.minor_id = 0
        WHERE T.object_id IN (SELECT object_id FROM sys.Tables)";

            return CPQuery.From(strSQL).FillDataTable();
        }
    }
}
View Code

    2.BackgroundWorker

     除了本身使用Thread或者ThreadPool來實現跨線程更新UI還可使用BackgroundWorker組件來實現該效果。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Mysoft.Map.Extensions.DAL;
using System.Collections;
using Mysoft.Code.Services;
using System.IO;
using System.Threading;

namespace ThreadWin
{
    public partial class BackgroundWorkerForm : Form
    {
        //模版文件路徑
        private static string tmpPath = AppDomain.CurrentDomain.BaseDirectory + @"實體模版\Entity.vm";

        //模版輸出路徑
        private static string outPutPath = AppDomain.CurrentDomain.BaseDirectory + @"模版輸出路徑";

        private DataTable dtInfo = new DataTable();

        /// <summary>
        /// 消息發送請求委託
        /// </summary>
        /// <param name="Msg">消息</param>
        delegate void SetMessageCallBack(object Msg);

        public BackgroundWorkerForm()
        {
            InitializeComponent();
            dtInfo.Columns.Add("TableName");
            dtInfo.Columns.Add("Info");
            dtInfo.Columns.Add("Time");
            Control.CheckForIllegalCrossThreadCalls = false;
        }

        private void btn_OK_Click(object sender, EventArgs e)
        {
            dtInfo.Clear();
            

            if (!Directory.Exists(outPutPath))
            {
                Directory.CreateDirectory(outPutPath);
            }

            //判斷線程是否Busy
            if (mBackgroundWorker.IsBusy)
            {
                MessageBox.Show("當前進程正在生成代碼，請等待本次操做完成！");
                return;
            }
            mBackgroundWorker.RunWorkerAsync();
        }

        private void mBackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker bw = (BackgroundWorker)sender;

            //循環生成實體，而且在列表上顯示進度
            DataTable dt = GetAllTableInfo();
            DataView dv = dt.DefaultView;
            var query = (from p in dt.AsEnumerable()
                         group p by new { TableId = p.Field<int>("tableid"), TableName = p.Field<string>("table_name") } into q
                         select new { TableId = q.Key.TableId, TableName = q.Key.TableName }
                        );
            foreach (var key in query)
            {
                dv.RowFilter = "tableid=" + key.TableId;
                DataTable dtTable = dv.ToTable();
                Hashtable ht = new Hashtable();
                ht["T"] = dtTable;
                string tableName = dtTable.Rows[0]["table_name"].ToString();
                FileGen.GetFile(tmpPath, ht, string.Format("{0}\\{1}.cs", outPutPath, key.TableName));

                //消息提示
                DataRow dr = dtInfo.NewRow();
                dr["TableName"] = tableName;
                dr["Info"] = "生成成功";
                dr["Time"] = DateTime.Now.ToString();
                dtInfo.Rows.Add(dr);
                DataView dvOrder = dtInfo.DefaultView;
                dvOrder.Sort = "Time DESC";
                DataTable dtinfo = dvOrder.ToTable();
                //通知進度改變
                bw.ReportProgress(0, dtinfo);
            } 
        }

        /// <summary>
        /// 進度改變執行
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void mBackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            dataGridView.DataSource = e.UserState;
        }

        /// <summary>
        /// 獲取全部表信息
        /// </summary>
        /// <returns></returns>
        public DataTable GetAllTableInfo()
        {
            string strSQL = @"    SELECT T.name AS table_name ,
            T.object_id AS tableid,
            ISNULL(CONVERT(VARCHAR(MAX), E.value), '') AS table_name_c ,
            C.name AS field_name ,
            ISNULL(CONVERT(VARCHAR(MAX), D.value), '') AS field_name_c ,
            ROW_NUMBER() OVER(PARTITION BY T.name ORDER BY C.colid) AS field_sequence ,
            TYPE_NAME(C.xtype) AS date_type ,
            (CASE WHEN EXISTS ( SELECT   1
            FROM     sysobjects
            WHERE    xtype = 'PK'
            AND name IN (
            SELECT  name
            FROM    sysindexes
            WHERE   id = C.id
            AND indid IN (
            SELECT  indid
            FROM    sysindexkeys
            WHERE   id = C.id
            AND colid = C.colid ) ) )
            THEN 1
            ELSE 0
            END) AS pk ,
            ISNULL(C.isnullable, 1) AS isnullable ,
            ISNULL(COLUMNPROPERTY(c.id, c.name, 'IsIdentity'), 0) AS isidentity
            FROM   sys.tables AS T
            LEFT JOIN syscolumns AS C ON c.id = T.object_id
            LEFT JOIN sys.extended_properties AS D ON D.major_id = T.object_id
            AND D.minor_id = C.colid
            AND D.major_id = C.id
            LEFT JOIN sys.extended_properties AS E ON E.major_id = T.object_id
            AND E.minor_id = 0
        WHERE T.object_id IN (SELECT object_id FROM sys.Tables)";

            return CPQuery.From(strSQL).FillDataTable();
        }
    }
}
View Code

    1.操做步驟很簡單，從組件裏面拖一個BackgroundWorker組件設置WorkerReportsProgress（是否容許通知進度改變）爲true

    2.添加DoWork(進行耗時操做) 和 ProgressChanged(進度改變執行) 方法

本章總結

     在寫數據字典生成工具以前本身對線程的使用仍是很模糊的，翻了不少資料和博客才學習到這些知識。若是您感受本文不錯，對您有所幫助，請您不吝點擊下右邊的推薦按鈕，謝謝！

     本章代碼示例代碼下載地址：http://code.taobao.org/svn/DataDic_QuickCode ，請使用SVN進行下載！

工具源代碼下載

      目前總共有通過了七個版本的升級，如今提供最新版本的下載地址

學習使用

      若是你使用了該工具，或者想學習該工具，歡迎加入這個小組，一塊兒討論數據字典生成工具、把該工具作的更強，更方便使用，一塊兒加入147425783 QQ羣。

      更多數據字典生成工具資料請點擊數據字典生成工具專題。

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