c#基于NVelocity實(shí)現(xiàn)代碼生成

更新時間：2021年01月25日 08:40:55 作者：code2roc

這篇文章主要介紹了c#基于NVelocity實(shí)現(xiàn)代碼生成的方法，幫助大家更好的理解和使用c#，感興趣的朋友可以了解下

在框架開發(fā)過程中，通用代碼生成是一項(xiàng)必不可少的功能，c#在這后端模板引擎這方面第三方組件較少，我這里選擇的是NVelocity，現(xiàn)在升級到了NetStandard2.0，可以用于NetCore項(xiàng)目

添加引用

初始化模板引擎及設(shè)置模板讀取路徑

vltEngine = new VelocityEngine();
      vltEngine.SetProperty(RuntimeConstants.RESOURCE_LOADER, "file");
      vltEngine.SetProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, CloudUtil.GetContentPath() + "/" + "Template");
      vltEngine.Init();

讀取模板渲染結(jié)果

VelocityContext vltContext = new VelocityContext();
      foreach (var item in RenderDataDic)
      {
        vltContext.Put(item.Key, item.Value);
      }
      Template vltTemplate = vltEngine.GetTemplate(TemplateFileName);
      System.IO.StringWriter vltWriter = new System.IO.StringWriter();
      vltTemplate.Merge(vltContext, vltWriter);
      string CodeContent = vltWriter.GetStringBuilder().ToString();

模板語法

示例Entity模板

using FastORM.Attribute;
using FastORM.Entity;
using System;
using System.Collections.Generic;
using System.Text;

namespace ${NameSpace}.Entity
{
  [Table(Name = "${TablePhysicalNameLowCase}")]
  public class ${TablePhysicalName} : BaseEntity
  {
    [Key]
    public string RowGuid { set; get; }
    #foreach( $Column in $ColumnList)
    #if (($Column.ColumnType == 10 || $Column.ColumnType == 50) && $Column.PhysicalColumnName!="RowGuid")
    public string $Column.PhysicalColumnName { set; get; }
    #end
    #if ($Column.ColumnType == 20 && $Column.PhysicalColumnName!="RowGuid")
    public int $Column.PhysicalColumnName { set; get; }
    #end
    #if ($Column.ColumnType == 30 && $Column.PhysicalColumnName!="RowGuid")
    public decimal $Column.PhysicalColumnName { set; get; }
    #end
    #if ($Column.ColumnType == 40 && $Column.PhysicalColumnName!="RowGuid")
    public DateTime? $Column.PhysicalColumnName { set; get; }
    #end
    #end
  }
}

常用語法

使用${xxx}占位替換具體字符串內(nèi)容

使用 #foreach( $Itemin $ItemList) #end 來進(jìn)行循環(huán)渲染

使用 #if #end 來進(jìn)行分支判斷渲染

完整工具類代碼

public class TemplateUtil
  {
    private static VelocityEngine vltEngine;
    public static string CodeTempPath;

    private static void InitTemplateSetting()
    {
      CodeTempPath = AppConfigUtil.Configuration["Frame:GenerateCodeTemplatePath"];
      DirectoryInfo CodePath = new DirectoryInfo(CloudUtil.GetContentStaticFilePath() + CodeTempPath);
      if (!CodePath.Exists)
      {
        CodePath.Create();
      }
      vltEngine = new VelocityEngine();
      vltEngine.SetProperty(RuntimeConstants.RESOURCE_LOADER, "file");
      vltEngine.SetProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, CloudUtil.GetContentPath() + "/" + "Template");
      vltEngine.Init();
    }

    public static string GeneratemeplateFile(string FileID, string TableName, string TemplateFileName, string CodeFileName, Dictionary<string, object> RenderDataDic)
    {
      InitTemplateSetting();
      DirectoryInfo CodePath = new DirectoryInfo(CloudUtil.GetContentStaticFilePath() + CodeTempPath + "/" + FileID);
      if (!CodePath.Exists)
      {
        CodePath.Create();
      }
      CodePath = new DirectoryInfo(CloudUtil.GetContentStaticFilePath() + CodeTempPath + "/" + FileID + "/" + TableName);
      if (!CodePath.Exists)
      {
        CodePath.Create();
      }
      VelocityContext vltContext = new VelocityContext();
      foreach (var item in RenderDataDic)
      {
        vltContext.Put(item.Key, item.Value);
      }
      Template vltTemplate = vltEngine.GetTemplate(TemplateFileName);
      System.IO.StringWriter vltWriter = new System.IO.StringWriter();
      vltTemplate.Merge(vltContext, vltWriter);
      string CodeContent = vltWriter.GetStringBuilder().ToString();
      string CodeFilePath = CloudUtil.GetContentStaticFilePath() + CodeTempPath + "/" + FileID + "/" + TableName + "/" + CodeFileName;
      //保存生成后的代碼內(nèi)容到文件
      FileUtil.SaveStringToFile(CodeFilePath, CodeContent);
      return CodeFilePath;
    }

    public static string GenerateTemplateContent(string TemplateFileName, Dictionary<string, object> RenderDataDic)
    {
      InitTemplateSetting();
      VelocityContext vltContext = new VelocityContext();
      foreach (var item in RenderDataDic)
      {
        vltContext.Put(item.Key, item.Value);
      }
      Template vltTemplate = vltEngine.GetTemplate(TemplateFileName);
      System.IO.StringWriter vltWriter = new System.IO.StringWriter();
      vltTemplate.Merge(vltContext, vltWriter);
      string CodeContent = vltWriter.GetStringBuilder().ToString();
      return CodeContent;
    }
  }

以上就是c#基于NVelocity實(shí)現(xiàn)代碼生成的詳細(xì)內(nèi)容，更多關(guān)于NVelocity實(shí)現(xiàn)代碼生成的資料請關(guān)注腳本之家其它相關(guān)文章！

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