CODEWITHSUNDEEP
javafilejakarta-eeinputstream
viswa
viswa

Reputation: 351

Java- using an InputStream as a File

I'm trying to generate a PDF document from an uploaded ".docx" file using JODConverter. The call to the method that generates the PDF is something like this :

File inputFile = new File("document.doc");
File outputFile = new File("document.pdf");

// connect to an OpenOffice.org instance running on port 8100
OpenOfficeConnection connection = new SocketOpenOfficeConnection(8100);
connection.connect();

// convert
DocumentConverter converter = new OpenOfficeDocumentConverter(connection);
converter.convert(inputFile, outputFile);

// close the connection
connection.disconnect();

I'm using apache commons FileUpload to handle uploading the docx file, from which I can get an InputStream object. I'm aware that Java.io.File is just an abstract reference to a file in the system.

I want to avoid the disk write (saving the InputStream to disk) and the disk read (reading the saved file in JODConverter).

Is there any way I can get a File object refering to an input stream? just any other way to avoid disk IO will also do!

EDIT: I don't care if this will end up using a lot of system memory. The application is going to be hosted on a LAN with very little to zero number of parallel users.

Upvotes: 2

Views: 3317

Answers (3)

JoG
JoG

Reputation: 6732

Chances are that commons fileupload has written the upload to the filesystem anyhow.

Check if your FileItem is an instance of DiskFileItem. If this is the case the write implementation of DiskFileItem willl try to move the file to the file object you pass. You are not causing any extra disk io then since the write already happened.

Upvotes: 1

imxylz
imxylz

Reputation: 7937

File-based conversions are faster than stream-based ones (provided by StreamOpenOfficeDocumentConverter) but they require the OpenOffice.org service to be running locally and have the correct permissions to the files.

Try the doc to avoid disk writting:

convert(java.io.InputStream inputStream, DocumentFormat inputFormat, java.io.OutputStream outputStream, DocumentFormat outputFormat)

Upvotes: 2

fge
fge

Reputation: 121710

There is no way to do it and make the code solid. For one, the .convert() method only takes two Files as arguments.

So, this would mean you'd have to extend File, which is possible in theory, but very fragile, as you are required to delve into the library code, which can change at any time and make your extended class non functional.

(well, there is a way to avoid disk writes if you use a RAM-backed filesystem and read/write from that filesystem, of course)

Upvotes: 2

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