VS Extension+NVelocity系列(一)——构建一个简单的NVelocity解析环境

阅读目录

一、前言
二、项目搭建
三、说明
四、还有些要说的

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一、前言

本节我们将实际实现一个简单的NVelocity解析环境,以便为以后的实例做一些基本工作,虽然NVelocity如何使用已经属于老掉牙的话题,但我只能专门挑出来一章来做铺垫.人生就是这样无奈啊.不过请您放心,不会耗去您太多的时间.

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二、项目搭建

1.新建一个”ASP.Net 空Web应用程序”,.Net版本请选择4,项目命名为:SW.VMTest,并”为解决方案创建目录”
2.在解决方案下再新建一个类库项目:SW.VMTest.Library
3.续上文，在SW.VMTest.Library 上引用您下载到的4.0/NVelocity.dll

4.新建一个NVelocityEngine类:

using Commons.Collections;
using NVelocity;
using NVelocity.App;
using System;
using System.Collections;
using System.IO;
using System.Web;
 
namespace SW.VMTest.Library
{
    public class NVelocityEngine
    {
        public VelocityContext Context { get; set; }
 
        private VelocityEngine _Engine { get; set; }
 
        public NVelocityEngine(HttpContext httpContext)
        {
            ExtendedProperties ep = new ExtendedProperties();
            //#foreach 计数器初始值
            ep.AddProperty("directive.foreach.counter.initial.value", 0);
            //是否允许设置为null
            ep.AddProperty("directive.set.null.allowed", false);
            //模板路径
            ep.AddProperty("file.resource.loader.path", AppDomain.CurrentDomain.BaseDirectory + "\\Template");
            _Engine = new VelocityEngine(ep);
 
            //Context init
            Hashtable hs = new Hashtable();
            hs.Add("Session", httpContext.Session);
            hs.Add("Request", httpContext.Request);
            hs.Add("Server", httpContext.Server);
            hs.Add("ObjHelper", new ObjectHelper());
            Context = new VelocityContext(hs);
        }
 
        public bool Merge(string templateName, TextWriter writer)
        {
            bool result = _Engine.MergeTemplate(templateName, "UTF-8", Context, writer);
            if (!result)
                _Engine.Error("模板解析失败！");
            return result;
        }
 
        public bool Evaluate(TextWriter writer, string inString)
        {
            bool result = _Engine.Evaluate(Context, writer, "Error", inString);
            if (!result)
                _Engine.Error("模板解析失败！");
            return result;
        }
    }
}

5.继续在在SW.VMTest.Library 项目上引用System.Web

6.新建一个SHtmlHandler类:

using System.IO;
using System.Web;
 
namespace SW.VMTest.Library
{
    public class SHtmlHandler : IHttpHandler
    {
        public bool IsReusable
        {
            get { return false; }
        }
 
        public void ProcessRequest(HttpContext context)
        {
            NVelocityEngine _nVe = new NVelocityEngine(context);
            string filePath = context.Request.Path.TrimStart('\\').Replace(".shtml", ".vm");
 
            StringWriter writer = new StringWriter();
            _nVe.Merge(filePath, writer);
 
            context.Response.Clear();
            context.Response.Write(writer);
            context.Response.End();
        }
    }
}

7.在SW.VMTest.Library上新建一个文件夹,命名为Helper

8.在Helper文件夹内新建一个ObjectHelper类:

using System;
 
namespace SW.VMTest.Library
{
    public class ObjectHelper
    {
        public object GetObject(string typeName)
        {
            return GetObject(typeName, null);
        }
 
        public object GetObject(string typeName, params object[] args)
        {
            Type type = Type.GetType(typeName);
            if (type == null)
                throw new ArgumentException("找不到具体的类型");
            object obj;
            if (args != null)
                obj = Activator.CreateInstance(type, args);
            else
                obj = Activator.CreateInstance(type);
            return obj;
        }
    }
}

9.在SW.VMTest项目上修改Web.config文件:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.0" />
    <httpHandlers>
      <add path="*.shtml" verb="*" type="SW.VMTest.Library.SHtmlHandler, SW.VMTest.Library"/>
    </httpHandlers>
  </system.web>
</configuration>

10.在SW.VMTest项目上创建新文件夹Template
11.Template文件夹上点右键,选择”在文件资源管理器中打开此文件”
12.在打开的文件夹中创建一个空白的.txt文档,并修改文件名为”test.vm”

13.点击vs”工具”->”选项”->”文本编辑器”->”文件扩展名”,添加如下图项目,确定

<a href="//images0.cnblogs.com/blog/193899/201408/191143429249410.png" rel="noopener nofollow"><img

style="background-image: none; border-width: 0; padding-left: 0; padding-right: 0; display: inline; padding-top: 0" title="image" border="0" alt="image" src="//images0.cnblogs.com/blog/193899/201408/191143447069752.png" width="604" height="394"></

a>

1	`14.点击解决方案管理中的”显示文件”按钮`

<a href="//images0.cnblogs.com/blog/193899/201408/191141282535265.png" rel="noopener nofollow"><img

style="background-image: none; border-width: 0; padding-left: 0; padding-right: 0; display: inline; padding-top: 0" title="image" border="0" alt="image" src="//images0.cnblogs.com/blog/193899/201408/191141291284166.png" width="244" height="100"></

a>

15.找到Template文件夹下的Test.vm,右击,选择”包含进项目”

16.打开Test.vm文件,输入以下代码:

<html>
<head>
    <title>Test Page</title>
</head>
<body>
    <h1>Hello World</h1>
    <ul>
        #foreach($item in [1..5])
        <li>I'm the list$item with index $velocityCount</li>
        #end
    </ul>
    <p>$Server.MapPath('aaa.aspx')</p>
    <p>$Request.QueryString.get_item('aa')</p>
    #set($dictionary = $ObjHelper.GetObject('System.Collections.Generic.Dictionary`2[[System.Int32],[System.Int32]]'))
    $dictionary.Add(1,123)
    $dictionary.Add(2,223)
    $dictionary.Add(3,323)
    <p>$dictionary.get_item(1)</p>
</body>
</html>

17.运行,输入以下地址:
http://localhost:3205/test.shtml?aa=hahaha
18.请确认是否为以下界面,如果不,请检查步骤.