java - 如何使用 Spring MVC 从 url 下载文件？

Question

我的 jsp 中有这样的下载选项

<a href='<c:url value="/licensing/download.sp?name=${namelist.name}&downloadUrl=${namelist.url}"/>'>

<img src="/images/download.gif" alt="Download" border="0" align="right">

在上面的“url”是文件的位置，name是文件名。在jsp中点击下载选项时，我调用 Controller 方法下载，在 Controller 中

public ModelAndView download(HttpServletRequest request, HttpServletResponse response, DevTechBean devTechBean) throws Exception {
        cat.debug("MySuiteListController: download: begin");
        ModelAndView modelView = super.handleLicensingRequest(request, response);
        String name = request.getParameter("name");

        String url1 = request.getParameter("downloadUrl");
        cat.debug(" download: url ="+url1);

        String downloadurl1="https://my.net:8869"+url1;
        cat.debug(" download: downloadurl ="+downloadurl1);
    try{
        URL url = new URL(downloadurl1);  
        //response.setHeader("Content-Type", "text/csv");  
        response.setHeader("Content-disposition", "attachment;filename="+name);
        URLConnection connection = url.openConnection();
        InputStream stream = connection.getInputStream();
        BufferedOutputStream outs = new BufferedOutputStream(response.getOutputStream());
        int len;
        byte[] buf = new byte[1024];
        while ((len = stream.read(buf)) > 0) {
          outs.write(buf, 0, len);
        }
        outs.close();
    }
    catch (MalformedURLException e) { 
        cat.error("Error occurrred in url");

    } 
    catch (IOException e) { 
        cat.error("Error occurrred ");

    }
        String viewName = "swl_download";
    modelView.setViewName(viewName);
return modelView;       

}

但是当我点击下载时，我收到文件未找到异常。我认为问题是由于 url 值引起的。在上面的 iam 中，值为 downloadurl=/files/download/hai.txt

当我给予

<a href="${namelist.url}"/>
<img src="/images/download.gif" alt="Download" border="0" align="right"></a><br/><br/></td>

单击后，文件将在浏览器中打开，网址为 https://my.net:8869//files/download/hai.txt(but这里的 href iam 只给出了这个链接“/files/download/hai.txt”不知道整个链接是怎么来的。

但是如果给出这样的链接来调用 Controller 打开该文件作为弹出窗口。

<a href='<c:url value="/download.sp?name=${namelist.name}&downloadUrl=${namelist.url}"/>'>

它正在获取文件未找到异常。我认为是因为 downloadUrl.so 我在上面添加了这样的内容

String downloadurl1="https://my.net:8869"+url1;

但我收到文件未找到异常。请帮我解决这个问题。

Answer 1

试试这个:

@RequestMapping(value="/viewAttach", method = RequestMethod.GET)
public ModelAndView viewAttach(@RequestParam(value="article_id", required = true) String article_ref, HttpSession session, HttpServletResponse response) 
{

    /* *** Check Session *** */
    try {

        // Direclty from pier.content.GetContent written by ang94402

        URL url = new URL(binaryURL);           
        response.setHeader("Content-disposition", "attachment;filename=" + binary.getName());

        //Set the mime type for the response
        response.setContentType("application/pdf");

        // URLConnection connection = url.openConnection();
        InputStream is = url.openStream();

        BufferedOutputStream outs = new BufferedOutputStream(response.getOutputStream());
        int len;
        byte[] buf = new byte[1024];
        while ( (len = is.read(buf)) > 0 ) {
            outs.write(buf, 0, len);
        }
        outs.close();

    } catch (MalformedURLException e) {
        logger.error("Error ModelAndView.viewMain - MalformedURLException : " + e.toString() + " -- " + e.getStackTrace()[0].toString());
        return null;
    } catch (IOException e) {
        logger.error("Error ModelAndView.viewMain - IOException : " + e.toString() + " -- " + e.getStackTrace()[0].toString());
        return null;
    }


    return null;

}