模版引擎之简单实现

本文转载自查看原文 2012-07-18 11:45 1576 模版引擎/ 模版引擎之简单实现

模版，大家肯定都比较熟悉的一个概念，刚学C#（Java）那会老师就告诉我们，类是对象的模版。今天写这个模版其实是我用于生成js代码的，当然不限于生成js,其实跟codesmith有着差不多的功能，只是没那么强大，下面我写一些思路

我这个模版目前用于生成Ext的Grid和添加，编辑表单，所以主角的又（怎么会是又呢，呵呵）是数据库表，不过这些信息被我存到前一篇博客里提到的Model里去了（通过特性的方式）。

出于方便，我还是把Model的代码贴一下：

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= " 编号 ")]
        [DataMember(Order = 0)]
         public   long? AgentID{ get; set;}


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


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


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


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

    }
}

没错，这些信息被存放于储如“[Column(ColumnName="AgentLevelID",ForeignKeyTableName="AgentLevel",ForeignKeyFiledName="AgentLevelID", DbType=SqlDbType.Int, Index=1,Description="等级编号")]”这行特性标记中，稍作解释

ColumnName ：列名，ForeignKeyTableName：外键表名，ForeignKeyFiledName：外键表的主键列名，DbType：字段类型，Description：描述

有了这些基本信息，便够了，现在我们就来解释上一篇讲到的数据库表数据的浏览功能，主角（模版）登场，分步实现

1.定义模块标签，现在模版功能还不是很强大，没有实现语法分析如if等，目前只是简单的实现了for和标签替换，上代码

模块标签定义

public const string ColumnEachTagName = " columnsEach "; // 循环列
         public const string DateColumnTagName = " dateColumn ";   // 日期列
         public const string PkColumnTagName = " pkColumn ";       // 主键列
         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 "; // 数字列
         public const string MoneyColumnTagName = " moneyColumn ";   // money型列
         public const string ColumnNameTagName = " [columnName] ";   // 列名
         public const string UnlessLastTagName = " unlessLast ";     // 除非最后一个
         public const string TableTagName = " [table] ";             // 表名
         public const string FkColumnTagName = " fkColumn ";         // 外键列名
         public const string FkTableTagName = " [fkTable] ";         // 外键表名
         public const string ColumnDescriptionTagName = " [columnDescription] ";   // 列描述
         public const string PkColumnNameTagName = " [pkColumnName] ";    // 主键列名

通过上面代码，我们可以将标签划分为三类

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

2.语法类，如columnsEach，unlessLast

3.筛选类如dateColumn,pkColumn,textColumn,boolColumn……

2.写模版文件

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);

}

看到这个模块，也就清楚如果写了，一个标记，我们得让程序知道从哪里开始，又从哪里结束，所以我这里以@tagName:开始，@<tagName结束，所以我的TagIndex类里也依赖这一点

3.进行语法分析和替换动作

这是很重要的一步了，要操作标签，首先我们得找到标签。很简单，一个IndexOf就足够了，但是我要稍微封装一下，如下：

找到标签的类

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}这一结束标记 ", tagName));
             return new TagIndex { TagName = tagName, Source = str };
        }
    }
}

标签找到之后，便是分析替换，像上面的[table]（占位符类）标签，我们当然直接替换就可以了，但是语法类的我们还得稍加分析才行，拿columnsEach举例吧，上伪代码

   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 =>
                {
                      // 去替换里面的占位符类标签
                }

}

再来看看unlessLast标签，定义这个标签的用意在于，最后一行就不输出标签里面的内容，使用场景如：给表格加入列时，最后一列我们不需要加逗号，见下图(当然不是只针对这种场景)

如上图，第一处有“,” 第二处则没有，要实现这一点，我们在模版文件里这样写

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

}@unlessLast:, @<unlessLast@<everyColumn

可能有人会说，这也太大材小用了吧，呵呵，希望你能提出意见，我现在只想到这种方式。下面把所有代码粘过来，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 "; // 循环列
         public const string DateColumnTagName = " dateColumn ";   // 日期列
         public const string PkColumnTagName = " pkColumn ";       // 主键列
         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 "; // 数字列
         public const string MoneyColumnTagName = " moneyColumn ";   // money型列
         public const string ColumnNameTagName = " [columnName] ";   // 列名
         public const string UnlessLastTagName = " unlessLast ";     // 除非最后一个
         public const string TableTagName = " [table] ";             // 表名
         public const string FkColumnTagName = " fkColumn ";         // 外键列名
         public const string FkTableTagName = " [fkTable] ";         // 外键表名
         public const string ColumnDescriptionTagName = " [columnDescription] ";   // 列描述
         public const string PkColumnNameTagName = " [pkColumnName] ";    // 主键列名

         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,这里整个过程也就差不多结束了（不知道怎么替换？当然是Replace）

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