It depends on the browser and container, but ignore it at your own risk. The safest solution is to set the content length to the exact size before writing any data to the response.
If the data is being computed on the fly, then write your data to a ByteArrayOutputStream first, then use byte data[] = ByteArrayOutputStream.toByteArray() to get something to send to the response. Here's an example of what might happen if you don't. http://lists.samba.org/archive/jcifs/2003-May/002188.html On 10/25/05, CONNER, BRENDAN (SBCSI) <[EMAIL PROTECTED]> wrote: > In earlier examples, one had to call response.setContentLength() with > the number of bytes being passed. I have the following questions > regarding this: > > 1. What are the consequences if I get the length wrong? Does it have to > be exact? > 2. Can the setContentLength() be called after I have done all the > writes, or must it be done before the writes? If I can call it > beforehand, then I can compute the length as I go. Otherwise, it will > be more difficult. > > Thanks, > > - Brendan > > -----Original Message----- > From: CONNER, BRENDAN (SBCSI) > Sent: Tuesday, October 25, 2005 12:15 PM > To: 'MyFaces Discussion' > Subject: RE: AW: FileDownload capability? > > > And it's even easier if one is generating a text file (rather than a > binary file), for example, when writing out a comma-separated file for > use in a spreadsheet, since one can use > response.getWriter().print(String s) and > response.getWriter().println(String s). > > - Brendan > > -----Original Message----- > From: Nico Krijnen [mailto:[EMAIL PROTECTED] > Sent: Tuesday, October 25, 2005 3:00 AM > To: 'MyFaces Discussion' > Cc: [EMAIL PROTECTED] > Subject: RE: AW: FileDownload capability? > > > It is actualy much easier in JSF. You just need to have an action method > in > a (managed) bean, like this: > > > public String downloadFile() { > FacesContext facesContext = FacesContext.getCurrentInstance(); > if (!facesContext.getResponseComplete()) { > String fileName = "myfile.pdf"; > > ServletContext servletContext = (ServletContext) > facesContext.getExternalContext().getContext(); > String contentType = > servletContext.getMimeType(fileName); > > HttpServletResponse response = (HttpServletResponse) > facesContext.getExternalContext().getResponse(); > response.setContentType(contentType); > response.setHeader("Content-Disposition", > "attachment;filename=\"" + fileName + "\""); > > try { > InputStream in = /* get your data */; > ServletOutputStream out = > response.getOutputStream(); > > byte[] buf = new byte[512]; > int bytesRead; > while ((bytesRead = in.read(buf, 0, bufSize)) != > -1) > { > out.write(buf, 0, bytesRead); > } > > out.flush(); > facesContext.responseComplete(); > } catch (IOException e) { > throw new RuntimeException(e); > } > } > return null; > } > > > Then you can simply call the method from a commandLink or commandButton > > > <h:commandLink action="#{yourBean.downloadFile}"> > <h:outputText value="download" /> > </h:commandLink> > > > Nico > > > -----Oorspronkelijk bericht----- > Van: news [mailto:[EMAIL PROTECTED] Namens Werner Punz > Verzonden: maandag 24 oktober 2005 23:34 > Aan: [email protected] > Onderwerp: Re: AW: FileDownload capability? > > It is rather easy, I usually have a download servlet for this > which generates the appropriate html code, I do not have the code handy > currently > but you basically set the header mimetype to either your filetype or > application/octed > stream, then pass down the content length (this is important because > otherwise our all beloved IE > has some problems on certain filetypes) > and then you basically pass the stream as content down as embedded > binary > data. > > You also can achieve that with a phaselistener if you feel uneasy to do > it > over > a separate servlet. > > All you then have to do is to link to the servlet or phase listener with > a > linke > and a target="_new" > > Werner > > > [EMAIL PROTECTED] wrote: > > I have nearly the same problem: > > > > I have the link of a sample file (pdf, doc or something else) in the > database. > > Now the user should have the possibility to open this file via a > CommandButton or CommandLink > > > > I'm not quite sure, how I can do this? > > Thx for help > > > > > >
