通过分段表单数据上传时如何知道文件大小? [英] How to know the file size when uploading via multipart form-data?

问题描述

我正在使用HTML客户端运行一个简单的应用程序，该应用程序将文件上传到服务器，并且必须显示进度栏:)

I am exercising a simple application with HTML client that uploads a file to the server and must display a progress bar :)

服务器是基于servlet的，一些servlet接收多部分内容，然后对其进行解析等.显然，每时每刻我都知道到目前为止接收到的字节数.但是，为了在客户端提供进度条的信息，servlet还需要文件的字节总数，该文件正被上传.知道从哪里获取字节总数吗?

The server is servlet-based, some servlet receives the multipart content, parses it etc. Obviously, at every moment I know the number of bytes received so far. However in order to supply an info for the progress bar on the client side a servlet also needs the total number of bytes for the file, which is being uploaded. Any idea where to get the total number of bytes from please?

谢谢！

推荐答案

内容大小位于Content-Length标头中(请参见 rfc2616 ).在Servlet中，您可以通过request.getContentLength()或reqest.getHeaders("Content-Length")

Size of content are placed in Content-Length header (see rfc2616). In Servlet you can get this header's value by request.getContentLength() or reqest.getHeaders("Content-Length")

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