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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")

Output Streaming multiple files into a zip file

Hie , I m generating report in csv format using solr , angularjs , Jax-rs and java. The input stream contain a csv response already because we have specified wt=csv while querying solr. Size of csv created from every input Stream might be 300mb .At java layer code is some thing like :
enter code here
InputStream is1;
InputStream is2;
// for is1 let file is csv1
// for is2 let file is csv2
// csvzip is the csv created form both two files
// now csvzip need to be downloaded through a popup
Creating big size file and zipfile in memory will not be a good approach surely.
Is there is any way to handle this?

How to convert a BLOB to pdf or csv using itext

My goal is to display the appropriate file, when the user clicks on a pdf or xls link.
The contents of a pdf or xlsfile are stored as a blob in a table. A stored procedure takes the file id as an input parameter and returns the blob as output.
I want to be able to display the file and am not sure how to go about it. On doing some reading it looks like i could use itest.
Is there a way to convert the blob to a pdf(or xls), using itext. Is this possible?
I was unable to find any examples that use a blob datatype.

(can't comment on David solution due to low reputation)
If the content on the BLOB record is a PDF binary data, you actually don't need to do anything with iText.
If you are not saving the BLOB to disk before and want (acording to your description) to just display, you could set the content type on the HTTP Response to indicate the browser how to deal with it:
response.setContentType("application/pdf"); // for PDF
response.setContentType("application/vnd.ms-excel"); // For BIFF .xls files
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"); // For Excel2007 and above .xlsx files

The IOUtils class in the Apache Commons IO library has a method copy which will copy all the bytes from an InputStream to an OutputStream. See the Javadoc.
So once you've got your blob and your HTTP response, you can just write
OutputStream httpOutputStream = httpResponse.getOutputStream();
InputStream blobInputStream = theBlob.getBinaryStream();
IOUtils.copy(blobInputStream, httpOutputStream);
blobInputStream.close();
httpOutputStream.close();
to copy the data. Or you might want to put the two close() calls in a finally block.
If you're not already using Apache Commons, don't forget to download the jar and add it to your classpath.

Commons Net FTPClient retrieved file encoding issue

I'm retrieving a file from a FTP Server. The file is encoded as UTF-8
ftpClient.connect(props.getFtpHost(), props.getFtpPort());
ftpClient.login(props.getUsername(), props.getPassword());
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
inputStream = ftpClient.retrieveFileStream(fileNameBuilder
.toString());
And then somewhere else I'm reading the input stream
bufferedReader = new BufferedReader(new InputStreamReader(
inputStream, "UTF-8"));
But the file is not getting read as UTF-8 Encoded!
I tried ftpClient.setAutodetectUTF8(true); but still doesn't work.
Any ideas?
EDIT:
For example a row in the original file is
...00248090041KENAN SARÐIN 00000000015.993FAC...
After downloading it through FTPClient, I parse it and load in a java object, one of the fields of the java object is name, which for this row is read as "KENAN SAR�IN"
I tried dumping to disk directly:
File file = new File("D:/testencoding/downloaded-file.txt");
FileOutputStream fop = new FileOutputStream(file);
ftpClient.retrieveFile(fileName, fop);
if (!file.exists()) {
file.createNewFile();
}
I compared the MD5 Checksums of the two files(FTP Server one and the and the one dumped to disk), and they're the same.

I would separate out the problems first: dump the file to disk, and compare it with the original. If it's the same as the original, the problem has nothing to do with UTF-8. The FTP code looks okay though, and if you're saying you want the raw binary data, I'd expect it not to mess with anything.
If the file is the same after transfer as before, then the problem has nothing to do with FTP. You say "the file is not getting read as UTF-8 Encoded" but it's not clear what you mean. How certain are you that it's UTF-8 text to start with? If you could edit your question with the binary data, how it's being read as text, and how you'd expect it to be read as text, that would really help.

Try to download the file content as bytes and not as characters using InputStream and OutputStream instead of InputStreamReader. This way you are sure that the file is not changed during transfer.

error in sending image from android to java app serially -javax.imageio.IIOException: Bogus Huffman table definition

I need to send image from android app to java app. Basically, I need a byte array from the image to send to rf module which transmits.Another rf module receives and sends the byte array to java app which must make the image .
Android code:
FileInputStream fis = new FileInputStream(myFile);
byte[] b=new byte[(int)myFile.length()];
fis.read(b);server.send(b);
Java code:
FileOutputStream fwrite = new FileOutputStream(new File("my_xml"),true);
fwrite.write(bb);//bb is a byte from rf using input stream as soon as a byte comes it is read to file. This is necessary for some other reasons
fwrite.flush();
fwrite.close();
After getting full file:
FileInputStream fir=new FileInputStream("my_xml");
final BufferedImage bufferedImage = ImageIO.read(fir);
ImageIO.write(bufferedImage, "bmp", new File("image.bmp"));
fir.close();
I am getting error javax.imageio.IIOException: Bogus Huffman table definition
The rf is working fine because text file is being sent perfectly.Please help.Even without ImageIo code is not giving image even after changing extension to jpeg

The error means that the image file cant be read because the format is wrong.That is some bytes are missing or wrong or out of proper position and therefore file cant be decoded. My rf transfer does not have protocols like tcp/ip therefore some bytes are lost due to error in communication channel and hence the error.

You don't need to use ImageIO just to copy a file. Just read and write the bytes.
Your code has other problems:
You are assuming that read(byte[]) fills the buffer. It doesn't. Check the Javadoc.
You are also assuming that the file length fits into an int. If it does, fine. If it doesn't, you are hosed.
You appear to be opening and closing the FileOutputStream on every byte received. This could not be more inefficient. Open it once, write everything, close it.
flush() before close() is redundant.
You are storing the image in a file called 'my_xml'. This is only going to cause confusion, if it hasn't already.
You don't even need the file. Just load the image directly from the input stream.