模版引擎之簡單實現

本文轉載自查看原文 2012-07-18 11:45 1576 模版引擎/ 模版引擎之簡單實現

模版，大家肯定都比較熟悉的一個概念，剛學C#（Java）那會老師就告訴我們，類是對象的模版。今天寫這個模版其實是我用於生成js代碼的，當然不限於生成js,其實跟codesmith有着差不多的功能，只是沒那么強大，下面我寫一些思路

我這個模版目前用於生成Ext的Grid和添加，編輯表單，所以主角的又（怎么會是又呢，呵呵）是數據庫表，不過這些信息被我存到前一篇博客里提到的Model里去了（通過特性的方式）。

出於方便，我還是把Model的代碼貼一下：

Model

// ------------------------------------------------------------------------------
// <auto-generated>
//      This code generated by the tool, do not propose to amend
//        Generation time:2012/7/16 18:01:54
// </auto-generated>
// ------------------------------------------------------------------------------
using System;
using System.Data;
using System.Runtime.Serialization;
using XDbFramework;
using System.Xml.Serialization;
using System.Diagnostics;
using System.CodeDom.Compiler;

namespace ExinSoft.Host.Model
{
    [Serializable]
    [Table(TableName = " Agent " ,Descripton = " 代理 ")]
      [GeneratedCodeAttribute( " System.Xml ", " 2.0.50727.4927 ")]
    [DebuggerStepThroughAttribute()]
    [XmlRootAttribute(Namespace = " http://www.scexin.com/ ", IsNullable = true)]
    [DataContract(Namespace = " http://www.scexin.com/ ")]
     public partial class Model_Agent
    {

        [Column(KeyType = KeyTypeEnum.PrimaryKey,ColumnName= " AgentID ",DbType=SqlDbType.BigInt, Index= 0,Description= " 編號 ")]
        [DataMember(Order = 0)]
         public   long? AgentID{ get; set;}


        [Column(ColumnName= " AgentLevelID ",ForeignKeyTableName= " AgentLevel ",ForeignKeyFiledName= " AgentLevelID ", DbType=SqlDbType.Int, Index= 1,Description= " 等級編號 ")]
        [DataMember(Order = 1)]
         public   int? AgentLevelID{ get; set;}


        [Column(ColumnName= " SuperiorAgentID ",ForeignKeyTableName= " Agent ",ForeignKeyFiledName= " AgentID ", DbType=SqlDbType.BigInt, Index= 2,Description= " 套餐編號 ")]
        [DataMember(Order = 2)]
         public   long? SuperiorAgentID{ get; set;}


        [Column(ColumnName= " CustomerID ",ForeignKeyTableName= " Customers ",ForeignKeyFiledName= " CustomerID ", DbType=SqlDbType.BigInt, Index= 3,Description= " 客戶編號 ")]
        [DataMember(Order = 3)]
         public   long? CustomerID{ get; set;}


        [Column(ColumnName= " AddTime ",DbType=SqlDbType.DateTime, Index= 4,Description= " 操作時間 ")]
        [DataMember(Order = 4)]
         public  DateTime? AddTime{ get; set;}

    }
}

沒錯，這些信息被存放於儲如“[Column(ColumnName="AgentLevelID",ForeignKeyTableName="AgentLevel",ForeignKeyFiledName="AgentLevelID", DbType=SqlDbType.Int, Index=1,Description="等級編號")]”這行特性標記中，稍作解釋

ColumnName ：列名，ForeignKeyTableName：外鍵表名，ForeignKeyFiledName：外鍵表的主鍵列名，DbType：字段類型，Description：描述

有了這些基本信息，便夠了，現在我們就來解釋上一篇講到的數據庫表數據的瀏覽功能，主角（模版）登場，分步實現

1.定義模塊標簽，現在模版功能還不是很強大，沒有實現語法分析如if等，目前只是簡單的實現了for和標簽替換，上代碼

模塊標簽定義

public const string ColumnEachTagName = " columnsEach "; // 循環列
         public const string DateColumnTagName = " dateColumn ";   // 日期列
         public const string PkColumnTagName = " pkColumn ";       // 主鍵列
         public const string TextColumnTagName = " textColumn ";   // 文本列
         public const string BoolColumnTagName = " boolColumn ";   // bool列
         public const string EveryColumnTagName = " everyColumn "; // 所有列
         public const string NumberColumnTagName = " numberColumn "; // 數字列
         public const string MoneyColumnTagName = " moneyColumn ";   // money型列
         public const string ColumnNameTagName = " [columnName] ";   // 列名
         public const string UnlessLastTagName = " unlessLast ";     // 除非最后一個
         public const string TableTagName = " [table] ";             // 表名
         public const string FkColumnTagName = " fkColumn ";         // 外鍵列名
         public const string FkTableTagName = " [fkTable] ";         // 外鍵表名
         public const string ColumnDescriptionTagName = " [columnDescription] ";   // 列描述
         public const string PkColumnNameTagName = " [pkColumnName] ";    // 主鍵列名

通過上面代碼，我們可以將標簽划分為三類

1.占位符類，如[table],[pkColumnName]，[columnDescription]

2.語法類，如columnsEach，unlessLast

3.篩選類如dateColumn,pkColumn,textColumn,boolColumn……

2.寫模版文件

模版文件

var [table]AddPostUrl = ' /proc/[table]/?action=add ';
var [table]UpdatePostUrl = ' /proc/[table]/?action=update ';
var [table]Form;
var [table]IdStr;
function initAdd[table]Form(containerid, idstr,rowObj) {
     if (!idstr)
        [table]IdStr = containerid;
     else
        [table]IdStr = idstr;
    [table]Form = new Ext.FormPanel({
        labelWidth: 100, // label settings here cascade unless overridden
        url: [table]AddPostUrl,
        frame: true,
        bodyStyle: ' padding:5px 5px 0 ',
        buttonAlign: ' left ',
        defaults: { width: 350 },
        defaultType: ' textfield ',
        renderTo: containerid,
        items: [
@columnsEach:
@pkColumn:
            {
                xtype: ' hidden ',
                name: ' [columnName] ',
                id: ' [columnName] ' + idstr,
                value: null == rowObj ? null : rowObj. get( ' [columnName] '),
                readOnly: true
            }@unlessLast:, @<unlessLast@<pkColumn
    @everyColumn:
            {
                xtype: ' textfield ',
                fieldLabel: ' [columnDescription] ',
                name: ' [columnName] ',
                allowBlank: false,
                value: null == rowObj ? null : rowObj. get( ' [columnName] '),
                id: ' [columnName] ' + idstr
            }@unlessLast:, @<unlessLast@<everyColumn
    @dateColumn:
            {
                xtype: ' datefield ',
                fieldLabel: ' [columnDescription] ',
                name: ' [columnName] ',
                allowBlank: false,
                value: null == rowObj || !Ext.isDate(rowObj. get( ' [columnName] ')) ? null : rowObj. get( ' [columnName] ').dateFormat( ' Y-m-d H:i:s '),format: ' Y-m-d H:i:s ',
                id: ' [columnName] ' + idstr
            }@unlessLast:, @<unlessLast@<dateColumn
    @<columnsEach
            ],
            buttons: getAddOrEditButton( ' [table] ')
    });

@columnsEach:
    @fkColumn:
    $( ' #[columnName] ' + idstr).focus(function() {
        loadGrid( ' [fkTable] ', this, $( ' #hidden[columnName] ' + idstr)[ 0], ' [columnName] ');
    });@<fkColumn

@<columnsEach


if (Ext.getCmp(containerid + ' _tab '))
    Ext.getCmp(containerid + ' _tab ').add([table]Form);

}

看到這個模塊，也就清楚如果寫了，一個標記，我們得讓程序知道從哪里開始，又從哪里結束，所以我這里以@tagName:開始，@<tagName結束，所以我的TagIndex類里也依賴這一點

3.進行語法分析和替換動作

這是很重要的一步了，要操作標簽，首先我們得找到標簽。很簡單，一個IndexOf就足夠了，但是我要稍微封裝一下，如下：

找到標簽的類

using System;

namespace TemplateEngine
{
     public class TagIndex
    {
         public bool FindThisTag { get { return Start >= 0; } }
         public int Start
        {
             get
            {
                 return Source.IndexOf( " @ " + TagName, System.StringComparison.Ordinal);
            }
        }
         public int End
        {
             get
            {
                 return Source.IndexOf( " @< " + TagName, System.StringComparison.Ordinal); ;
            }
        }
         public string Source { get; set; }
         public string TagName { get; set; }
         public string Content
        {
             get
            {
                 return Source.Substring(Start + string.Format( " @{0}: ", TagName).Length, End - Start - string.Format( " @<{0} ", TagName).Length);
            }
        }

         public string RealContent
        {
             get
            {
                 return Source.Substring(Start, End - Start + string.Format( " @<{0} ", TagName).Length);
            }
        }

         public static TagIndex GetTag( string str, string tagName)
        {
             var startOfAt = str.IndexOf( " @ " + tagName, System.StringComparison.Ordinal);
             if (startOfAt < 0)
                 return new TagIndex { TagName = tagName, Source = str };
             var endOfAt = str.IndexOf( " @< " + tagName, System.StringComparison.Ordinal);
             if (endOfAt < 0) throw new FormatException( string.Format( " 模版缺少@<{0}這一結束標記 ", tagName));
             return new TagIndex { TagName = tagName, Source = str };
        }
    }
}

標簽找到之后，便是分析替換，像上面的[table]（占位符類）標簽，我們當然直接替換就可以了，但是語法類的我們還得稍加分析才行，拿columnsEach舉例吧，上偽代碼

   var forTag = TagIndex.GetTag(str, " columnEach ");
             while (forTag.FindThisTag)
            {
                 var forStr = forTag.RealContent;
                 string fields = string.Empty;

                MathTag mathTag = new MathTag(forStr);

                columns.ForEach(m =>
                {
                      // 去替換里面的占位符類標簽
                }

}

再來看看unlessLast標簽，定義這個標簽的用意在於，最后一行就不輸出標簽里面的內容，使用場景如：給表格加入列時，最后一列我們不需要加逗號，見下圖(當然不是只針對這種場景)

如上圖，第一處有“,” 第二處則沒有，要實現這一點，我們在模版文件里這樣寫

@everyColumn:
            {
                xtype: 'textfield',
                fieldLabel: '[columnDescription]',
                name: '[columnName]',
                allowBlank: false,
                value: null == rowObj ? null : rowObj.get('[columnName]'),
                id: '[columnName]' + idstr

}@unlessLast:, @<unlessLast@<everyColumn

可能有人會說，這也太大材小用了吧，呵呵，希望你能提出意見，我現在只想到這種方式。下面把所有代碼粘過來，有需要的可以改改.

Generator

using System.IO;
using System.Text;
using XDbFramework;

namespace TemplateEngine
{
     public class Generator
    {
         public const string ColumnEachTagName = " columnsEach "; // 循環列
         public const string DateColumnTagName = " dateColumn ";   // 日期列
         public const string PkColumnTagName = " pkColumn ";       // 主鍵列
         public const string TextColumnTagName = " textColumn ";   // 文本列
         public const string BoolColumnTagName = " boolColumn ";   // bool列
         public const string EveryColumnTagName = " everyColumn "; // 所有列
         public const string NumberColumnTagName = " numberColumn "; // 數字列
         public const string MoneyColumnTagName = " moneyColumn ";   // money型列
         public const string ColumnNameTagName = " [columnName] ";   // 列名
         public const string UnlessLastTagName = " unlessLast ";     // 除非最后一個
         public const string TableTagName = " [table] ";             // 表名
         public const string FkColumnTagName = " fkColumn ";         // 外鍵列名
         public const string FkTableTagName = " [fkTable] ";         // 外鍵表名
         public const string ColumnDescriptionTagName = " [columnDescription] ";   // 列描述
         public const string PkColumnNameTagName = " [pkColumnName] ";    // 主鍵列名

         private readonly string _template;

         public Generator( string templatePath)
        {
             using ( var reader = new StreamReader(templatePath, encoding: Encoding.UTF8))
            {
                _template = reader.ReadToEnd();
            }
        }

         public string Generate<T>() where T : class
        {
             var table = DalHelper.GetTableInfo( typeof(T));
             var columns = DalHelper.GetTypeColumns<T>();
             var str = _template.Replace(TableTagName, table.TableName);
             var pkColumn = columns.Find(m => m.KeyType == KeyTypeEnum.PrimaryKey);
             if (pkColumn != null)
                str = str.Replace(PkColumnNameTagName, pkColumn.ColumnName);

             var forTag = TagIndex.GetTag(str, ColumnEachTagName);
             while (forTag.FindThisTag)
            {
                 var forStr = forTag.RealContent;
                 string fields = string.Empty;

                MathTag mathTag = new MathTag(forStr);

                columns.ForEach(m =>
                {
                     string tmpStr = string.Empty;
                    TagIndex tag = mathTag.GetTagIndexByColumn(m);
                     if (tag != null)
                    {
                        tmpStr = tag.Content
                            .Replace(ColumnNameTagName, m.ColumnName)
                            .Replace(ColumnDescriptionTagName, m.Description)
                            .Replace(FkTableTagName, m.ForeignKeyTableName);
                    }
                     var unlessLastTag = TagIndex.GetTag(tmpStr, UnlessLastTagName);
                     if (unlessLastTag.FindThisTag)
                    {
                         if (m == columns[columns.Count - 1])
                        {
                            tmpStr = tmpStr.Replace(unlessLastTag.RealContent, string.Empty);
                        }
                         else
                        {
                            tmpStr = tmpStr.Replace(unlessLastTag.RealContent, unlessLastTag.Content);
                        }
                    }
                    fields += tmpStr;
                });

                str = str.Replace(forStr, fields);
                forTag = TagIndex.GetTag(str, ColumnEachTagName);
            }
             return str;
        }
    }
}

MathTag

using System;
using XDbFramework;

namespace TemplateEngine
{
     public class MathTag
    {
         private string _sourceString;
         private TagIndex pkTag;
         private TagIndex fkTag;
         private TagIndex textTag;
         private TagIndex dateTag;
         private TagIndex numberTag;
         private TagIndex moneyTag;
         private TagIndex boolTag;
         private TagIndex everyTag;

         public MathTag( string sourceString)
        {
            _sourceString = sourceString;
            pkTag = TagIndex.GetTag(sourceString, Generator.PkColumnTagName);
            fkTag = TagIndex.GetTag(sourceString, Generator.FkColumnTagName);
            textTag = TagIndex.GetTag(sourceString, Generator.TextColumnTagName);
            dateTag = TagIndex.GetTag(sourceString, Generator.DateColumnTagName);
            numberTag = TagIndex.GetTag(sourceString, Generator.NumberColumnTagName);
            moneyTag = TagIndex.GetTag(sourceString, Generator.MoneyColumnTagName);
            boolTag = TagIndex.GetTag(sourceString, Generator.BoolColumnTagName);
            everyTag = TagIndex.GetTag(sourceString, Generator.EveryColumnTagName);
        }

         public TagIndex GetTagIndexByColumn(ColumnAttribute m)
        {
             if (m.KeyType == KeyTypeEnum.PrimaryKey && pkTag.FindThisTag)
            {
                 return pkTag;
            }
             if ((m.CType == typeof(DateTime) || m.CType == typeof(DateTime?)) && dateTag.FindThisTag)
            {
                 return dateTag;
            }
             if ((m.CType == typeof( bool) || m.CType == typeof( bool?)) && boolTag.FindThisTag)
            {
                 return boolTag;
            }
             if ((m.CType == typeof( float) || m.CType == typeof( decimal) || m.CType == typeof( double) || m.CType == typeof( float?) || m.CType == typeof( decimal?) || m.CType == typeof( double?)) && moneyTag.FindThisTag)
            {
                 return moneyTag;
            }
             if ((m.CType == typeof( int) || m.CType == typeof( int?) || m.CType == typeof( long) || m.CType == typeof( long?)) && numberTag.FindThisTag)
            {
                 return numberTag;
            }
             if (m.CType == typeof( string) && textTag.FindThisTag)
            {
                 return textTag;
            }
             if (m.KeyType == KeyTypeEnum.ForeignKey && fkTag.FindThisTag)
            {
                 return fkTag;
            } if (everyTag.FindThisTag)
            {
                 return everyTag;
            }
             return null;
        }
    }
}

好,這里整個過程也就差不多結束了（不知道怎么替換？當然是Replace）

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