Develop Reference

Creating a text file with java without using absolute path

following the question I asked before How to have my java project to use some files without using their absolute path? I found the solution but another problem popped up in creating text files that I want to write into.here's my code:
private String pathProvider() throws Exception {
//finding the location where the jar file has been located
String jarPath=URLDecoder.decode(getClass().getProtectionDomain().getCodeSource().getLocation().getPath(), "UTF-8");
//creating the full and final path
String completePath=jarPath.substring(0,jarPath.lastIndexOf("/"))+File.separator+"Records.txt";
return completePath;
}
public void writeRecord() {
try(Formatter writer=new Formatter(new FileWriter(new File(pathProvider()),true))) {
writer.format("%s %s %s %s %s %s %s %s %n", whichIsChecked(),nameInput.getText(),lastNameInput.getText()
,idInput.getText(),fieldOfStudyInput.getText(),date.getSelectedItem().toString()
,month.getSelectedItem().toString(),year.getSelectedItem().toString());
successful();
} catch (Exception e) {
failure();
}
}
this works and creates the text file wherever the jar file is running from but my problem is that when the information is been written to the file, the numbers,symbols, and English characters are remained but other characters which are in Persian are turned into question marks. like: ????? 111 ????? ????.although running the app in eclipse doesn't make this problem,running the jar does.
Note:I found the code ,inside pathProvider method, in some person's question.

Your pasted code and the linked question are complete red herrings - they have nothing whatsoever to do with the error you ran into. Also, that protection domain stuff is a hack and you've been told before not to write data files next to your jar files, it's not how OSes (are supposed to) work. Use user.home for this.
There is nothing in this method that explains the question marks - the string, as returned, has plenty of issues (see above), but NOT that it will result in question marks in the output.
Files are fundamentally bytes. Strings are fundamentally characters. Therefore, when you write code that writes a string to a file, some code somewhere is converting chars to bytes.
Make sure the place where that happens includes a charset encoding.
Use the new API (I think you've also been told to do this, by me, in an earlier question of yours) which defaults to UTF-8. Alternatively, specify UTF-8 when you write. Note that the usage of UTF-8 here is about the file name, not the contents of it (as in, if you put persian symbols in the file name, it's not about persian symbols in the contents of the file / in the contents you want to write).
Because you didn't paste the code, I can't give you specific details as there are hundreds of ways to do this, and I do not know which one you used.
To write to a file given a String representing its path:
Path p = Paths.get(completePath);
Files.write("Hello, World!", p);
is all you need. This will write as UTF_8, which can handle persian symbols (because the Files API defaults to UTF-8 if you specify no encoding, unlike e.g. new File, FileOutputStream, FileWriter, etc).
If you're using outdated APIs: new BufferedWriter(new OutputStreamWriter(new FileOutputStream(thePath), StandardCharsets.UTF-8) - but note that this is a resource leak bug unless you add the appropriate try-with-resources.
If you're using FileWriter: FileWriter is broken, never use this class. Use something else.
If you're converting the string on its own, it's str.getBytes(StandardCharsets.UTF_8), not str.getBytes().

Java saving a file with special characters in file name

I'm having a problem on Java file encoding.
I have a Java program will save a input stream as a file with a given file name, the code snippet is like:
File out = new File(strFileName);
Files.copy(inStream, out.toPath());
It works fine on Windows unless the file name contains some special characters like Ö, with these characters in the file name, the saved file will display a garbled file name on Windows.
I understand that by applying JVM option -Dfile.encoding=UTF-8 this issue can be fixed, but I would have a solution in my code rather than ask all my users to change their JVM options.
While debugging the program I can see the file name string always shows the correct character, so I guess the problem is not about internal encoding.
Could someone please explain what went wrong behind the scene? and is there a way to avoid this problem programmatically? I tried get the bytes from the string and change the encoding but it doesn't work.
Thanks.

Using the URLEncoder class would work:
String name = URLEncoder.encode("fileName#", "UTF-8");
File output = new File(name);

Trailing null (\x00) characters when writing text to Accumulo

I am trying to write the name of a file into Accumulo. I am using accumulo-core-1.43.
For some reason, certain files seem to be written into Accumulo with trailing \x00 characters at the end of the name. The upload is coming through a Java servlet (using the jquery file upload plugin). In the servlet, I check the name of the file with a System.out.println and it looks normal, and I even tried unescaping the string with
org.apache.commons.lang.StringEscapeUtils.unescapeJava(...);
The actual writing to accumulo looks like this:
Mutation mut = new Mutation(new Text(checkSum));
Value val = new Value(new Text(filename).getBytes());
long timestamp = System.currentTimeMillis();
mut.put(new Text(colFam), new Text(EMPTY_BYTES), timestamp, val);
but nothing unusual showed up there (perhaps \x00 isn't escaped)? But then if I do a scan on my table in accumulo, there will be one or more \x00 in the file name.
The problem this seems to cause is that I return that string within XML when I retrieve a list of files (where it shows up) and pass that back to the browser, the the XSL that is supposed to render the information in the XML no longer works when there's these extra characters (not sure why that is the case either).
In chrome, for the response on these calls, I see that there's three red dots after the file name, and when I hover over it, \u0 pops up (which I think is a different representation of 0/null?).
Anyway, I'm just trying to figure out why this happens, or at the very least, how I can filter out \x00 characters before returning the file in Java. any ideas?

You are likely incorrectly using the Hadoop Text class -- this is not an error with Accumulo. Specifically, you make the mistake in your above example:
Value val = new Value(new Text(filename).getBytes());
You must adhere to the length of provided by the Text class. See the Text javadoc for more information. If you're using Hadoop-2.2.0, you can use the provided copyBytes method on Text. If you're on older version of Hadoop where this method doesn't yet exist, you can use something like the ByteBuffer class or the System.arraycopy method to get a copy of the byte[] with the proper limits enforced.

How to make string for file name?

I try to create file in storage and for file name I use webview.getTitle() string.
When I save file with name for example "Google.jpg" or "Foreca.jpg" it works well, but...
not all webpage titles is so clear.
For example:
"android - java.io.ioexception: open failed: einval (Invalid argument)
when saving a image to external storage - Stack Overflow:"
There is a lot of wrong characters, if I need this title put in file name.
Is there easy way to replace all this :;?!/<>- characters to ""?

Yes, you can use replaceAll():
String fileName = webview.getTitle();
filename = fileName.replaceAll("(\\p{Punct})","") // fixed \p
Check out the Java documentation for more.

Running a JavaScript command from MATLAB to fetch a PDF file

I'm currently writing some MATLAB code to interact with my company's internal reports database. So far I can access the HTML abstract page using code which looks like this:
import com.mathworks.mde.desk.*;
wb=com.mathworks.mde.webbrowser.WebBrowser.createBrowser;
wb.setCurrentLocation(ReportURL(8:end));
pause(1);
s={};
while isempty(s)
s=char(wb.getHtmlText);
pause(.1);
end
desk=MLDesktop.getInstance;
desk.removeClient(wb);
I can extract out various bits of information from the HTML text which ends up in the variable s, however the PDF of the report is accessed via what I believe is a JavaScript command (onClick="gotoFulltext('','[Report Number]')").
Any ideas as to how I execute this JavaScript command and get the contents of the PDF file into a MATLAB variable?
(MATLAB sits on top of Java, so I believe a Java solution would work...)

I think you should take a look at the JavaScript that is being called and see what the final request to the webserver looks like.
You can do this quite easily in Firefox using the FireBug plugin.
https://addons.mozilla.org/en-US/firefox/addon/1843
Once you have found the real server request then you can just request this URL or post to this URL instead of trying to run the JavaScript.

Once you have gotten the correct URL (a la the answer from pjp), your next problem is to "get the contents of the PDF file into a MATLAB variable". Whether or not this is possible may depend on what you mean by "contents"...
If you want to get the raw data in the PDF file, I don't think there is a way currently to do this in MATLAB. The URLREAD function was the first thing I thought of to read content from a URL into a string, but it has this note in the documentation:
s = urlread('url') reads the content
at a URL into the string s. If the
server returns binary data, s will
be unreadable.
Indeed, if you try to read a PDF as in the following example, s contains some text intermingled with mostly garbage:
s = urlread('http://samplepdf.com/sample.pdf');
If you want to get the text from the PDF file, you have some options. First, you can use URLWRITE to save the contents of the URL to a file:
urlwrite('http://samplepdf.com/sample.pdf','temp.pdf');
Then you should be able to use one of two submissions on The MathWorks File Exchange to extract the text from the PDF:
Extract text from a PDF document by Dimitri Shvorob
PDF Reader by Tom Gaudette
If you simply want to view the PDF, you can just open it in Adobe Acrobat with the OPEN function:
open('temp.pdf');

wb=com.mathworks.mde.webbrowser.WebBrowser.createBrowser;
wb.executeScript('javascript:alert(''Some code from a link'')');
desk=com.mathworks.mde.desk.MLDesktop.getInstance;
desk.removeClient(wb);