JAVA高级面试进阶训练营视频教程

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FileHandler http://www.cnblogs.com/vipsoft/p/3627709.html

UpdatePanel无法导出下载文件: http://www.cnblogs.com/vipsoft/p/3298299.html

//相对路径下载。path: ~/DownLoad/
//<add key="DownLoadPath" value="~/DownLoad/"/>
public static bool DownLoadFile(string path, string fileName)
{
    bool result = false; 
    try
    {
        string filePath = HttpContext.Current.Server.MapPath(path + fileName);
        if (File.Exists(filePath))
        { 
            FileInfo fileInfo = new FileInfo(filePath);
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearContent();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
            HttpContext.Current.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
            HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
            HttpContext.Current.Response.ContentType = "application/octet-stream";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
            HttpContext.Current.Response.WriteFile(fileInfo.FullName);
            HttpContext.Current.Response.Flush(); 
            HttpContext.Current.Response.End();
            result = true;
        }
    }
    catch
    { 
    } 
    return result;
}
 

//物理路径下载。path: D:\DownLoad\
//<add key="DownLoadPath" value="D:\DownLoad\"/>
public static bool DownLoadFile(string path, string fileName)
{
    bool result = false;
    string filePath = path + fileName;
    if (File.Exists(filePath))
    { 
        try
        {
            //string filePath = HttpContext.Current.Server.MapPath(path + fileName);
            
            FileInfo fileInfo = new FileInfo(filePath);
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearContent();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
            HttpContext.Current.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
            HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
            HttpContext.Current.Response.ContentType = "application/octet-stream";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
            HttpContext.Current.Response.WriteFile(fileInfo.FullName);
            HttpContext.Current.Response.Flush(); 
            result = true; 
        }
        catch (Exception e)
        {
        }
        finally
        {
            HttpContext.Current.Response.End();    //解决 ThreadAbortException 异常问题

        }
    } 
    return result;
}

 两种方法的结合

 public static bool DownLoadFile(string path, string fileName)
        {
            bool result = false;
            string filePath = path + fileName;
            if (File.Exists(filePath))
            {
                result = true;
            }
            else
            {
                try
                { 
                    filePath = HttpContext.Current.Server.MapPath(path + fileName);
                    if (File.Exists(filePath))
                    {
                        result = true;
                    }
                }
                catch 
                {
                    result = false;
                }
            }
            if (result)
            { 
                try
                {
                    //string filePath = HttpContext.Current.Server.MapPath(path + fileName); 
                    FileInfo fileInfo = new FileInfo(filePath);
                    HttpContext.Current.Response.Clear();
                    HttpContext.Current.Response.ClearContent();
                    HttpContext.Current.Response.ClearHeaders();
                    HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
                    HttpContext.Current.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
                    HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
                    HttpContext.Current.Response.ContentType = "application/octet-stream";
                    HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
                    HttpContext.Current.Response.WriteFile(fileInfo.FullName);
                    HttpContext.Current.Response.Flush();  
                }
                catch (Exception e)
                {
                }
                finally
                {
                    HttpContext.Current.Response.End();
                }
            }
            return result;
        }

 

根据一些业务逻辑返回相应的状态字符串，如果出现异常做返回“error”，我预期它返回“状态1”，结果测试时发现
AJAX回调的结果是“状态1error”，它居然抛出异常了！
google后得知：Response.End 方法终止页的执行，并将此执行切换到应用程序的事件管线中的
Application_EndRequest 事件,同时抛出ThreadAbortException 异常，异常信息为“正在中止线程”。另外
Response.Redirect、Server.Transfer方法也会出现这个问题，因为它们内部调用了Response.End 方法。
它给出的解决方案是使用HttpContext.Current.ApplicationInstance.CompleteRequest 方法以跳过
Application_EndRequest 事件的代码执行，但是我试了后发现虽然不抛出异常了，但是页面后面的代码依然会执行，
达不到Response.End的效果。

Response.End导致“正在中止线程”异常的问题，来源：

http://www.cnblogs.com/jintianhu/archive/2011/02/16/1952833.html