Develop Reference

Decoding excel file gone wrong

Hello I have a REST API in which I am uploading .xls files. Using the debugger I can see that the excel file is getting encoded correctly.
Code:
String[] tokensVal = request.getContent().split(delimiters);
String fileContentEncoded = tokensVal[tokensVal.length-1];
Result:
UEsDBBQABgAIAAAAIQAbOCctygEAAIsHAAATAM4BW0NvbnRlbnRfVHlwZXNdLnhtbCCiygEooAACAAAA...KxVy27bMBC8F+g/CLwWFp0eiiCwnEPSHNMAST6AIdcSYb7ApR3777uUIqM2FDWGfNF7Z3ZmH1rc7qwpthBRe1exq3LOCnDSK+3qir2+PMyuWYFJ...
When I am trying to decode the file with UTF-8 charset I can see that something is going wrong.
Code:
InputStream fileContent = new ByteArrayInputStream(new String(Base64.getDecoder().decode(fileContentEncoded), UTF_8).getBytes(UTF_8));
Result:
PK!8'-[Content_Types].xml (Un0? CI>!aﻔ"65|{gvfZ)Q{Wr
p+ꊽ<̮YI8%wP= ]~xVI)p+YhEX Z翸.K1rq+1]&oڱ.SUL`[NHf~K%Ba)C!%rWpjs)I(,w'$'݂(bTu=#A"<OZJ^Rd[5ltq=yqҮ)Ю{ 鞢ȩ֓<
Is anyone who faced this problem before?

equivalent to Files.readAllLines() for InputStream or Reader?

I have a file that I've been reading into a List via the following method:
List<String> doc = java.nio.file.Files.readAllLines(new File("/path/to/src/resources/citylist.csv").toPath(), StandardCharsets.UTF_8);
Is there any nice (single-line) Java 7/8/nio2 way to pull off the same feat with a file that's inside an executable Jar (and presumably, has to be read with an InputStream)? Perhaps a way to open an InputStream via the classloader, then somehow coerce/transform/wrap it into a Path object? Or some new subclass of InputStream or Reader that contains an equivalent to File.readAllLines(...)?
I know I could do it the traditional way in a half page of code, or via some external library... but before I do, I want to make sure that recent releases of Java can't already do it "out of the box".

An InputStream represents a stream of bytes. Those bytes don't necessarily form (text) content that can be read line by line.
If you know that the InputStream can be interpreted as text, you can wrap it in a InputStreamReader and use BufferedReader#lines() to consume it line by line.
try (InputStream resource = Example.class.getResourceAsStream("resource")) {
List<String> doc =
new BufferedReader(new InputStreamReader(resource,
StandardCharsets.UTF_8)).lines().collect(Collectors.toList());
}

You can use Apache Commons IOUtils#readLines:
List<String> doc = IOUtils.readLines(inputStream, StandardCharsets.UTF_8);

Not able to get the pdf from internet

I am trying to download the pdf content from the internet and download it to a local file.
I am using iText for reading the pdf and using Java stream to write it.
After writing the file, new file can not be opened in the PDF reader.
PdfReader reader = new PdfReader(strURL);
FileOutputStream fos = new FileOutputStream(new File(fileName));
fos.write(reader.getPageContent(1));
fos.flush();
fos.close();
I am trying to get the PDf from this link
I am debugged few things. Here are the findings.
reader.getEofPos()
gives 291633, Which is same as file length.But
reader.getPageContent(1).length;
gives only 42360 bytes. Clearly byte read are less than the actual size.
Only one page of pdf is present
reader.getNumberOfPages() =1
Do i need to specify few more things to reader to read the entire pdf file?

If all you're trying to do is download a PDF from the internet and save it locally, this can be accomplished using a simple HTTP web request. An internet download is normally just an HTTP GET request, which you can accomplish by doing something like this:
URLConnection connection = new URL(url).openConnection();
connection.setRequestProperty("Accept-Charset", charset);
InputStream response = connection.getInputStream();
Once you get the response, you can save the bytes to a path of your choosing.

Send a text file from URL directly into a scanner

I am using java and currently, I can download a text file from the internet, read that file, then send that file into a Scanner. Is it possible to skip writing it to the harddrive and send it straight into the scanner? I tried changing the code some, but it didn't work.
URL link = new URL("http://shayconcepts.com/programming/ComicDownloader/version.txt");
ReadableByteChannel rbc = Channels.newChannel(link.openStream());//Gets the html page
FileOutputStream fos = new FileOutputStream("version.txt");//Creates the output name of the output file to be saved to the computer
fos.getChannel().transferFrom(rbc, 0, 1 << 24);
fos.close();
Scanner sc = new Scanner(new FileReader("version.txt"));

Yes, it is definitely possible. Just do exactly like you said: feed the from the URL obtained input stream straight into the scanner.
Scanner sc = new Scanner(link.openStream());
It has namely also a constructor taking an input stream. It accepts by the way the charset as 2nd argument, you might want to make use of it if the text file is possibly in a different character encoding than the platform default one, otherwise you might risk Mojibake.
Scanner sc = new Scanner(link.openStream(), "UTF-8");

Corrupt file when using Java to download file

This problem seems to happen inconsistently. We are using a java applet to download a file from our site, which we store temporarily on the client's machine.
Here is the code that we are using to save the file:
URL targetUrl = new URL(urlForFile);
InputStream content = (InputStream)targetUrl.getContent();
BufferedInputStream buffered = new BufferedInputStream(content);
File savedFile = File.createTempFile("temp",".dat");
FileOutputStream fos = new FileOutputStream(savedFile);
int letter;
while((letter = buffered.read()) != -1)
fos.write(letter);
fos.close();
Later, I try to access that file by using:
ObjectInputStream keyInStream = new ObjectInputStream(new FileInputStream(savedFile));
Most of the time it works without a problem, but every once in a while we get the error:
java.io.StreamCorruptedException: invalid stream header: 0D0A0D0A
which makes me believe that it isn't saving the file correctly.

I'm guessing that the operations you've done with getContent and BufferedInputStream have treated the file like an ascii file which has converted newlines or carriage returns into carriage return + newline (0x0d0a), which has confused ObjectInputStream (which expects serialized data objects.

If you are using an FTP URL, the transfer may be occurring in ASCII mode.
Try appending ";type=I" to the end of your URL.

Why are you using ObjectInputStream to read it?
As per the javadoc:
An ObjectInputStream deserializes primitive data and objects previously written using an ObjectOutputStream.
Probably the error comes from the fact you didn't write it with ObjectOutputStream.
Try reading it wit FileInputStream only.
Here's a sample for binary ( although not the most efficient way )
Here's another used for text files.

There are 3 big problems in your sample code:
You're not just treating the input as bytes
You're needlessly pulling the entire object into memory at once
You're doing multiple method calls for every single byte read and written -- use the array based read/write!
Here's a redo:
URL targetUrl = new URL(urlForFile);
InputStream is = targetUrl.getInputStream();
File savedFile = File.createTempFile("temp",".dat");
FileOutputStream fos = new FileOutputStream(savedFile);
int count;
byte[] buff = new byte[16 * 1024];
while((count = is.read(buff)) != -1) {
fos.write(buff, 0, count);
}
fos.close();
content.close();

You could also step back from the code and check to see if the file on your client is the same as the file on the server. If you get both files on an XP machine, you should be able to use the FC utility to do a compare (check FC's help if you need to run this as a binary compare as there is a switch for that). If you're on Unix, I don't know the file compare program, but I'm sure there's something.
If the files are identical, then you're looking at a problem with the code that reads the file.
If the files are not identical, focus on the code that writes your file.
Good luck!