在 nvelocity 中是否有 URLResourceLoader 类的模拟

Question

我想通过使用url路径为位于外部服务器上的VelocityEnngine提供外部资源，在Apache velocity中有URLResourceLoader类，但我看到在NVelocity中只有FileRecourceLoader...

有没有办法在NVelocity中提供外部（url）资源扩展属性

提前谢谢。

Answer 1

我自己实现了接口：

public class UrlResourceLoader : ResourceLoader
{
    protected ArrayList paths;
    protected Hashtable templatePaths;
    public UrlResourceLoader()
    {
        templatePaths = new Hashtable();
    }

    public override void Init(ExtendedProperties configuration)
    {
        paths = configuration.GetVector("path");
    }
    public override Stream GetResourceStream(string templateName)
    {
        lock (this)
        {
            int size = paths.Count;
            if (string.IsNullOrEmpty(templateName))
            {
                throw;
            }
            for (int i = 0; i < size; i++)
            {
                var path = (string) paths[i];
                var uri = new Uri(path + templateName);
                Stream inputStream = FindTemplate(uri);
                if (inputStream != null)
                {
                    SupportClass.PutElement(templatePaths, templateName, path);
                    return inputStream;
                }
            }
            throw;
        }
    }
    private Stream FindTemplate(Uri requestUri)
    {
        try
        {
            var request = (HttpWebRequest)WebRequest.Create(requestUri);
            request.Method = "GET";
            var response = (HttpWebResponse) request.GetResponse();
            if (HttpStatusCode.OK != response.StatusCode)
            {
                throw;
            }
            return response.GetResponseStream();
        }
        catch (Exception ex)
        {
            throw;
        }
    }
    public override bool IsSourceModified(Resource resource)
    {
        var path = (string)templatePaths[resource.Name];
        var uri = new Uri(path + resource.Name);
        var request = (HttpWebRequest)WebRequest.Create(uri);
        request.Method = "GET";
        using (var response = (HttpWebResponse)request.GetResponse())
        {
            return response.LastModified.Ticks != resource.LastModified;
        }
    }
    public override long GetLastModified(Resource resource)
    {
        var path = (string)templatePaths[resource.Name];
        var uri = new Uri(path + resource.Name);
        var request = (HttpWebRequest)WebRequest.Create(uri);
        request.Method = "GET";
        using (var response = (HttpWebResponse)request.GetResponse())
        {
            return response.LastModified.Ticks;
        }
    }
}