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Velocity使用方法简介

时间：2010-02-04

来源：互联网

以前用winforms写模板生成，现在没必要了，有了Velocity(以下简称V），就可以写出web的模板生成了。

使用很简单，下载了之后，引用dll，我这里写了一个通用的类

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections;

using NVelocity;
using NVelocity.App;
using NVelocity;
using NVelocity.Runtime;
using Commons.Collections;
using System.IO;
using NVelocity.Context;
/// <summary>
/// BaseVelocity 的摘要说明
/// </summary>
public class BaseVelocity
{

/// <summary>
/// Common
/// </summary>
/// <param name="tempAbsPath">模板路径</param>
/// <param name="outAbsPath">输出绝对路径</param>
/// <param name="parameters">初始参数</param>
/// <param name="tempEncoding">模板编码[options]</param>
/// <param name="outEncoding">输出编码[optioins]</param>
/// <param name="returnStr"></param>
/// <returns></returns>
private string create(string tempAbsPath, string outAbsPath,Hashtable parameters,string tempEncoding, string outEncoding,bool returnStr)
{
      if (tempAbsPath == "") { throw new ArgumentException("模板参数错误"); }
      if (outAbsPath == "") { throw new ArgumentException("输出参数错误");  }
      if (tempEncoding == "") tempEncoding = "utf-8";
      if (outEncoding == "") outEncoding = "utf-8";

      //创建NVelocity引擎的实例对象
      VelocityEngine velocity = new VelocityEngine();

      //初始化该实例对象
      string root = tempAbsPath.Substring(0, tempAbsPath.LastIndexOf("\\") + 1);
      string fileName = tempAbsPath.Substring(tempAbsPath.LastIndexOf("\\") + 1);
      ExtendedProperties props = new ExtendedProperties();
      props.AddProperty(RuntimeConstants.RESOURCE_LOADER, "file");
      props.AddProperty(RuntimeConstants.INPUT_ENCODING, tempEncoding);
      props.AddProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, root);
      props.AddProperty(RuntimeConstants.OUTPUT_ENCODING, outEncoding);
      velocity.Init(props);

      //从文件中读取模板
      NVelocity.Template temp = velocity.GetTemplate(fileName);
      IContext context = new VelocityContext();
      if (parameters != null)
      {
         foreach (string key in parameters.Keys)
         {
            context.Put(key, parameters[key]);
         }
      }

      //合并模板
      StringWriter writer = new StringWriter();

      //velocity.MergeTemplate(context, writer);
      temp.Merge(context, writer);

      //生成静态页
      if (!returnStr)
      {
         using (StreamWriter writer2 = new StreamWriter(outAbsPath, false, System.Text.Encoding.GetEncoding(outEncoding), 200))
         {
            writer2.Write(writer);
            writer2.Flush();
            writer2.Close();
         }
      }
      else
         return writer.ToString();
      return null;
}
/// <summary>
/// 创建静态文件
/// </summary>
/// <param name="tempAbsPath">模板绝对路径</param>
/// <param name="outAbsPath">输出绝对路径</param>
/// <param name="parameters">初始参数</param>
/// <param name="tempEncoding">模板编码[options]</param>
/// <param name="outEncoding">输出编码[optioins]</param>
/// <param name="returnStr"></param>
/// <returns></returns>
public void creatFile(string tempAbsPath, string outAbsPath, Hashtable parameters, string tempEncoding, string outEncoding)
{
      create(tempAbsPath,outAbsPath,parameters,tempEncoding,outEncoding,false);
}
/// <summary>
/// 创建输出字符串
/// </summary>
/// <param name="tempAbsPath">模板绝对路径</param>
/// <param name="outAbsPath">输出绝对路径</param>
/// <param name="parameters">初始参数</param>
/// <param name="tempEncoding">模板编码[options]</param>
/// <param name="outEncoding">输出编码[optioins]</param>
/// <param name="returnStr"></param>
/// <returns></returns>
public string createStr(string tempAbsPath, string outAbsPath, Hashtable parameters, string tempEncoding, string outEncoding)
{
      return create(tempAbsPath, outAbsPath, parameters, tempEncoding, outEncoding, true);
}
}

这种是通过文件加载模板的

以下可以通过变量加载模板

关键代码：

System.Text.StringBuilder builder = new System.Text.StringBuilder();
      builder.Append("#foreach($u in $ListUsers)"r"n" +
         "#beforeall"r"n" +
         "<table border=""0"" cellpadding=""10"" cellspacing=""10"">" +
         "<tr><td>Name</td><td>Sex</td><td>City</td></tr>" +
         "#each"r"n" +
         "<tr>" +
         "<td>$u.Name</td>" +
         "<td>$u.Sex</td>" +
         "<td>$u.City</td>" +
         "</tr>" +
         "#afterall"r"n" +
         "</table>" +
         "#nodata"r"n" +
         "暂无用户资料"r"n" +
         "#end");

      VelocityEngine vltEngine = new VelocityEngine();
      vltEngine.Init();

      VelocityContext vltContext = new VelocityContext();
      vltContext.Put("PageTitle", "字符串模板例子");
      vltContext.Put("ListUsers", listUsers);

      System.IO.StringWriter vltWriter = new System.IO.StringWriter();
      vltEngine.Evaluate(vltContext, vltWriter, null, builder.ToString());

      Response.Write(vltWriter.GetStringBuilder().ToString());

转自：http://bbs.flatws.cn/thread-12225-1-1.html

作者: swlyb 发布时间: 2010-02-04

Velocity使用方法简介

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