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sending bytes as pdf

EDIT: The data I wanna send is in an rds. I fetch that into an output stream and then try to send it over as a pdf to the user.
The file gets generated but on opening the browser shows 'Failed to load PDF document.'
I have read that setting the ContentType to "application/pdf" helps but it does not in my case. The code is given below
byte[] b = generateFileService
.getDeviceHumidityRecordByPeriod(deviceIdValue, parseUnixTimestamp(startTime), parseUnixTimestamp(endTime));
OutputStream output = response.getOutputStream();
response.setContentType("application/pdf");
response.addHeader("Content-disposition", "attachment;filename=test.pdf");
output.write(b);
output.close();
response.flushBuffer();
}
if I change the file name to test.csv and then use content type as txt/plain, it works perfectly and a csv file is written.

I used Apache PDFBox to write data into a pdf file. The page offset needs to be tracked to add pages dynamically. Then you can convert the pdf into bytes and send it to the client by specifying response.setContentType("application/pdf") and response.addHeader("Content-disposition", "attachment;filename=test.pdf")

How to create a txt file with a String content and download that txt file

I am using java and struts. I have a scenario where there is 'Download' link in the page. After clicking on this link the control goes to the Action class, where I have String content which I need to write to a .txt file and then download that txt file.
Eventually whenever we click on the download link, we should be able to download a txt file having content a particular string.
I used below piece of code,
FileOutputStream outputStream = new FileOutputStream(fileNameWithDirectory);
outputStream.write(fileContentString.getBytes());
outputStream.close();
ActionForward forward = new ActionForward("doc/" + filename);
forward.setName(filename);
forward.setRedirect(true);
return forward;
Also I tried with FileWriter in place of FileOutputStream like,
FileWriter fileWriter = new FileWriter(fileNameWithDirectory);
fileWriter.write(fileContentString);
fileWriter.flush();
fileWriter.close();
But always instead of downloading the txt file, the control opens a new window where the String content is written.
Please suggest me, how would I able to download that .txt file.

You should add Content-Disposition: attachment to say browser, that it should download the file, not to open it.
See more details here
Also Struts has DownloadAction, you may use it as well.

You don't need to write the file and then redirect to it. You can set a http response header called Content-Disposition and then print your data into the http response body.
use it like this
response.addHeader("Content-Disposition", "Content-Disposition: attachment; filename=\""+filename+"\"");
of course this depends on which technology stack you're using.

Convert your text file to stream. and set content type as you wanted to download.
response.setContentType("application/pdf");
try {
// get your file as InputStream
InputStream is = ...;
// copy it to response's OutputStream
org.apache.commons.io.IOUtils.copy(is, convertedTextFiletoStream);
} catch (IOException ex) {
log.info("Error writing file to output stream. Filename was '{}'", fileName, ex);
throw new RuntimeException("IOError writing file to output stream");
}

Spring web application save file to server

I build a web application.
I would like to read files from server, then generate PDF file ( with itText) then save it to the server.
I don't know how to locate the files from the server then save the file to the server.
I read from my PC and write data to my PC perfectly.
The above code works properly but just on my computer not at server.
String jspPath = "C:\\Users\\dave\\Desktop\\eclipse\\project\\";
String fileName = "CV.txt";
InputStreamReader ir = new InputStreamReader(new FileInputStream(jspPath+filename), "UTF-8");
// Then generate the PDF with iText
//and
FileOutputStream fs = new FileOutputStream(jspPath+"generated.pdf");
PdfWriter pdfWriter = new PdfWriter(fs);
PdfDocument pdfdoc = new PdfDocument(pdfWriter);
JSP path references to my folder not the link with the generated pdf.
I would like :
put CV.txt to the server and read it.
Generate pdf ( it will work).
Save the generated PDF to server
A link to the generated PDF which i can download.
Thanks in Advance

Here are few things which might help you.
You can use FormData to pass text file from Frontend to Backend.
Use ajax post call to pass data.
you will have entire file on backend in the RequestContext parameter as FileItem object. you can start reading file using InputStreamReader.
than convert it into pdf file.
you can save pdf file to java temporary directory
String temporaryDir = System.getProperty("java.io.tmpdir");
this will return path for java temporary directory and you can delete this pdf file later
you will have to create ResponseBuilder with content-type='application/pdf' to download as a pdf file and return it to the UI. read this post
Hope this information helps you to solve your issue!

Append full PDF file to FOP PDF

I have an xml file already being created and rendered as a PDF sent over a servlet:
TraxInputHandler input = new TraxInputHandler(
new File(XML_LOCATION+xmlFile+".xml"),
new File(XSLT_LOCATION)
);
ByteArrayOutputStream out = new ByteArrayOutputStream();
//driver is just `new Driver()`
synchronized (driver) {
driver.reset();
driver.setRenderer(Driver.RENDER_PDF);
driver.setOutputStream(out);
input.run(driver);
}
//response is HttpServletResponse
byte[] content = out.toByteArray();
response.setContentType("application/pdf");
response.setContentLength(content.length);
response.getOutputStream().write(content);
response.getOutputStream().flush();
This is all working perfectly fine.
However, I now have another PDF file that I need to include in the output. This is just a totally separate .pdf file that I was given. Is there any way that I can append this file either to the response, the driver, out, or anything else to include it in the response to the client? Will that even work? Or is there something else I need to do?

We also use FOP to generate some documents, and we accept uploaded documents, all of which we eventually combine into a single PDF.
You can't just send them sequentially out the stream, because the combined result needs a proper PDF file header, metadata, etc.
We use the iText library to combine the files, starting off with
PdfReader reader = new PdfReader(/*String*/fileName);
reader.consolidateNamedDestinations();
We later loop through adding pages from each pdf to the new combined destination pdf, adjusting the bookmark / page numbers as we go.
AFAIK, FOP doesn't provide this sort of functionality.

Make a link to download local file

In my project (Java SpringMVC3) I get an XLS file via HttpClient and I want that file to be downloaded like it's a real download. A popup window showing download dialog.
How can I do that?

Controller should copy the content of file to response object. Do not forget - controller function must return NULL. Below I show a working example from my application:
String filename = /* path to a file */
File file = new File(filename);
response.setContentType(new MimetypesFileTypeMap().getContentType(file));
response.setContentLength((int)file.length());
response.setHeader("content-disposition", "attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
InputStream is = new FileInputStream(file);
FileCopyUtils.copy(is, response.getOutputStream());
return null;

Basically you need to implement a Controller that takes care of the download and specify the response's header-mime type. then you invoke that Controller from the view.
Here is a short example how to specify a header-mime type
HTTP Header Mime Type in Websphere Application Server 7