We Keep Coding

Download a file from JSP

I'm trying to download a file from JSP, but to no avail.
I created a button that calls a method in my controller
#RequestMapping(value = "scaricaFile", method = RequestMethod.POST)
public void getScaricaFile(HttpServletRequest request, HttpServletResponse response) {
String nome_file = request.getParameter("nome_file");
UploadAndDownload downloadFile = new UploadAndDownload();
downloadFile.download(nome_file, response);
}
the download function is
public void download(String allegato, HttpServletResponse response){
try {
File file = new File(path + allegato);
response.setContentType("application/download");
response.addHeader("Content-Disposition", "attachment; filename=" + file.getName());
response.setContentLength((int) file.length());
FileInputStream input = new FileInputStream(file);
BufferedInputStream buf = new BufferedInputStream(input);
FileCopyUtils.copy(buf, response.getOutputStream());
} catch (IOException e) {
System.out.println("Errore nel download del file!");
e.printStackTrace();
}
}
But on my chrome page the download does not open. Why?

Spring OutputStream - download pptx with IE

I use this Java code to download files from a web application:
#RequestMapping(value = "/filedownloads/filedownload/{userid}/{projectid}/{documentfileid}/{version}/", method = RequestMethod.GET)
public void filesDownload(final #PathVariable("userid") String userId, final #PathVariable("projectid") String projectId,
final #PathVariable("documentfileid") String documentFileId, final #PathVariable("version") String version,
final HttpServletResponse response) throws IOException, BusinessException {
...
final String fileName = "filename=" + documentFile.getFileName();
final InputStream is = new FileInputStream(filePath);
response.setHeader("Content-Disposition", "inline; " + fileName);
IOUtils.copy(is, response.getOutputStream());
response.flushBuffer();
}
if I will download a pptx- file I get the following IE- page:
What I want to do is to open the downloaded file in Powerpoint.
My question now would be if there is a header setting in order to open this file with the right application (in this case Powerpoint)

Simply try to set the Content Type header properly which is application/vnd.openxmlformats-officedocument.presentationml.presentation in case a pptx, as next:
response.setContentType(
"application/vnd.openxmlformats-officedocument.presentationml.presentation"
);
response.setHeader(
"Content-Disposition",
String.format("inline; filename=\"%s\"", documentFile.getFileName())
);
response.setContentLength((int) new File(filePath).length());
Here is the list of mime types corresponding to Office 2007 documents.

Here is a little sample code from a Spring MVC Controller:
#RequestMapping("/ppt")
public void downloadPpt(HttpServletRequest request, HttpServletResponse response) throws IOException {
Resource resource = new ClassPathResource("Presentation1.pptx");
InputStream resourceInputStream = resource.getInputStream();
response.setHeader("Content-Disposition", "attachment; filename=\"Presentation1.pptx\"");
response.setContentLengthLong(resource.contentLength());
byte[] buffer = new byte[1024];
int len;
while ((len = resourceInputStream.read(buffer)) != -1) {
response.getOutputStream().write(buffer, 0, len);
}
}
By setting the Content-Disposition to attachment, you're telling the browser to download this file as an attachment and by supplying the correct file name with extension, you're telling the Operating System to use whatever application the user normally uses to open a file of this type. In this case it will be MS Power Point.
This way you can get away with not knowing exactly what version of Power Point the file was created with.

I have tested code in IE-11 its work fine. See below code i.e
#RequestMapping(value = "/downloadfile", method = RequestMethod.GET)
#ResponseBody
public void downloadfile(HttpServletRequest request, HttpServletResponse response) throws Exception {
ServletOutputStream servletOutputStream = null;
try {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=downloadppt.pptx");
byte[] ppt = downloadFile();
servletOutputStream = response.getOutputStream();
servletOutputStream.write(ppt);
} catch (Exception e) {
throw e;
} finally {
servletOutputStream.flush();
servletOutputStream.close();
}
}
Generate bytes from saved pptx file.
public byte[] downloadFile() throws IOException {
InputStream inputStream = new FileInputStream(new File("e:/testppt.pptx"));
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
// Transfer bytes from source to destination
byte[] buf = new byte[1024];
int len;
while ((len = inputStream.read(buf)) > 0) {
byteArrayOutputStream.write(buf, 0, len);
}
inputStream.close();
byteArrayOutputStream.close();
return byteArrayOutputStream.toByteArray();
}
That's it, you are able to download pptx file. Hope code help you, if you have any query or doubt then we can discuss or if any suggestions. Thank you

file download pop up is not coming

Wrote a simple code to download a file from file system but still not getting download pop up hence file is not downloading ,not even throwing any error .Please help me out.Following is my code written on controller side.
#RequestMapping(value = "download", method=RequestMethod.POST)
public #ResponseBody void download(HttpServletRequest request, HttpServletResponse response){
String fileName="/home/test/Testing.xlsx";
PrintWriter out=null;
try{
System.out.println(fileName.substring(fileName.lastIndexOf('/')+1)+"fileName");
response.setContentType("application/vnd.ms-excel");
response.setHeader("Cache-Control", "must-revalidate");
response.setHeader( "Pragma", "public" );
response.setHeader("Content-Disposition", "attachment; filename=" + fileName.substring(fileName.lastIndexOf('/')+1) );
out = response.getWriter();
int i;
FileInputStream inputStream = new FileInputStream(fileName);
while ((i = inputStream.read()) != -1) {
out.write(i);
}
inputStream.close();
out.close();
}
catch(Exception e){
System.out.println(e);
}
}

here mistake was POST method, we should not use post method instead we should always use GET method while writing program for download.
#RequestMapping(value = "download", method=RequestMethod.GET)
public #ResponseBody void download(HttpServletRequest request, HttpServletResponse response){
String fileName="/home/test/Testing.xlsx";
PrintWriter out=null;
try{
System.out.println(fileName.substring(fileName.lastIndexOf('/')+1)+"fileName");
response.setContentType("application/vnd.ms-excel");
response.setHeader("Cache-Control", "must-revalidate");
response.setHeader( "Pragma", "public" );
response.setHeader("Content-Disposition", "attachment; filename=" + fileName.substring(fileName.lastIndexOf('/')+1) );
out = response.getWriter();
int i;
FileInputStream inputStream = new FileInputStream(fileName);
while ((i = inputStream.read()) != -1) {
out.write(i);
}
inputStream.close();
out.close();
}
catch(Exception e){
System.out.println(e);
}
}

HttpServletResponse prompt for file name on save

I used code similar to something below to return a zip file as an attachment to a SpringMVC request. The whole thing works great, I am able to download a file called hello.zip when I make a request to localhost/app/getZip.
My question here is, how can I prompt the user to enter a file name. Currently on FireFox25.0 it automatically assumes the name to be "hello.zip" without the provision to change the file name on Open or Save options.
#RequestMapping("getZip")
public void getZip(HttpServletResponse response)
{
OutputStream ouputStream;
try {
String content = "hello World";
String archive_name = "hello.zip";
ouputStream = response.getOutputStream();
ZipOutputStream out = new ZipOutputStream(ouputStream);
out.putNextEntry(new ZipEntry(“filename”));
out.write(content);
response.setContentType("application/zip");
response.addHeader("Content-Disposition", "attachment; filename="+ archive_name);
out.finish();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
TL;DR: Using HttpServletResponse I want user to provide a file name instead of passing one in the Header.

with method to RequestMethod.GET
URL : http://localhost/app/getZip?filename=hello.zip
#RequestMapping(value = "getZip/{filename}", method = RequestMethod.GET)
public void getZip(HttpServletResponse response, #PathVariable String filename)
{
OutputStream ouputStream;
try {
String content = "hello World";
String archive_name = "hello.zip";
ouputStream = response.getOutputStream();
ZipOutputStream out = new ZipOutputStream(ouputStream);
out.putNextEntry(new ZipEntry("filename"));
out.write(content);
response.setContentType("application/zip");
response.addHeader("Content-Disposition", "attachment; filename="+ archive_name);
out.finish();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}

How to send an Image from Mongo DB to Ext JS with an Java Servlet

I have an Java Servlet which tries to send an Image from Mongo DB to Ext JS:
#Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String action = req.getParameter("action");
if (action != null && action.equals("download")) {
resp.setContentType("text/html");
resp.setHeader("Content-Disposition", "attachment;filename=" + "images.jpg");
try {
DB db = DataBaseMongoService.getDb("forum_images"); //class that manages Mongo DB access
GridFS gfs = new GridFS(db, "image");
GridFSDBFile imageForOutput = gfs.findOne("images.jpg");
InputStream in = imageForOutput.getInputStream();
ServletOutputStream out = resp.getOutputStream();
out.write(IOUtils.toByteArray(in));
out.flush();
in.close();
out.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (NamingException e) {
e.printStackTrace();
}
}
}
My Ext JS call looks like this:
Ext.Ajax.request({
url: 'ForumImageServlet',
method: 'GET',
params: {
action: 'download'
},});
The Response is the bytestream of the image that looks like this:
����JFIF��� "" $(4,$&1'-=-157:::#+?D?8C49:77%w777777777777777777777777777777777777777777777777��Pp"��ï...

How can I get a real image as a response to my servlet?
Thanks in advance!

Why do you set ContentType to text/html?
Try using image/jpg

The final solution was encoding the bytestream to base64:
byte[] buf = IOUtils.toByteArray(in);
String prefix = "{\"url\":\"data:image/jpeg;base64,";
String postfix = "\"}";
String fileJson = prefix + Base64.encodeBytes(buf).replaceAll("\n", "") + postfix;
PrintWriter out = resp.getWriter();
out.write(fileJson);
out.flush();
in.close();
out.close();

instead of using ajax requests, you can inject an img-tag with src attribute. when you provide the correct mime-type, your browser loads the image