How do I replace illegal characters in a filename? - java

I am trying to create a zip with folders inside it and I have to sanitize the folder names against any illegal characters. I did some googling around and found this method from http://www.rgagnon.com/javadetails/java-0662.html:
public static String sanitizeFilename(String name) {
return name.replaceAll("[\\\\/:*?\"<>|]", "-");
}
However, upon testing I get some weird results. For example:
name = filename£/?e>"e
should return filename£--e--e from my understanding. But instead it returns filename-ú--e--e
Why is this so?
Please note that I am testing this by opening the downloaded zip file in WinZip and looking at the folder name that is created. I can't get the pound sign to appear. I've also tried this:
public static String sanitizeFilename(String name) {
name = name.replaceAll("[£]", "\u00A3");
return name.replaceAll("[\\\\/:*?\"<>|]", "-");
}
EDIT: Some more research and I found this: http://illegalargumentexception.blogspot.co.uk/2009/04/i18n-unicode-at-windows-command-prompt.html
It appears to do with Locale, windows versions and encoding factors. Not sure how I can overcome this within the code.

I think it depends on how you are actually reading the file name in terms of encoding.
Therefore, the £ symbol might get corrupted.
As an example not fitting your case exactly, reading UTF-8-encoded £ as an ISO Latin 1-encoded character would return £.
Make sure of the file's encoding (i.e. ISO Latin 1 vs UTF-8 would be the most common), then use the appropriate parameter for your Reader.
As a snippet, you may want to consider this example:
BufferedReader br = new BufferedReader(
new InputStreamReader(
new FileInputStream(new File("yourTextFile")),
"[your file's encoding]"
)
);

Related

How to handle  (object replacement character) in URL

Using Jsoup to scrape URLS and one of the URLS I keep getting has this  symbol in it. I have tried decoding the URL:
url = URLDecoder.decode(url, "UTF-8" );
but it still remains in the code looking like this:
I cant find much online about this other than it is "The object replacement character, sometimes used to represent an embedded object in a document when it is converted to plain text."
But if this is the case I should be able to print the symbol if it is plain text but when I run
System.out.println("");
I get the following complication error:
and it reverts back to the last save.
Sample URL: https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles%ef%bf%bc/
NOTE: If you decode the url then compare it to the decoded url it comes back as not the same e.g.:
String url = URLDecoder.decode("https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles%ef%bf%bc/", "UTF-8");
if(url.contains("https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles?/")){
System.out.println("The same");
}else {
System.out.println("Not the same");
}
That's not a compilation error. That's the eclipse code editor telling you it can't save the source code to a file, because you have told it to save the file in a cp1252 encoding, but that encoding can't express a .
Put differently, your development environment is currently configured to store source code in the cp1252 encoding, which doesn't support the character you want, so you either configure your development environment to store source code using a more flexible encoding (such as UTF-8 the error message suggests), or avoid having that character in your source code, for instance by using its unicode escape sequence instead:
System.out.println("\ufffc");
Note that as far as the Java language and runtime are concerned,  is a character like any other, so there may not be a particular need to "handle" it. Also, I am unsure why you'd expect URLDecoder to do anything if the URL hasn't been URL-encoded to begin with.
"ef bf bc" is a 3 bytes UTF-8 character so as the error says, there's no representation for that character in "CP1252" Windows page encoding.
An option could be to replace that percent encoding sequence with an ascii representation to make the filename for saving:
String url = URLDecoder.decode("https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles%ef%bf%bc/".replace("%ef%bf%bc", "-xEFxBFxBC"), "UTF-8");
url ==> "https://www.breightgroup.com/job/hse-advisor-emb ... contract-roles-xEFxBFxBC/"
Another option using CharsetDecoder
String urlDec = URLDecoder.decode("https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles%ef%bf%bc/", "UTF-8");
CharsetDecoder decoder = Charset.forName("CP1252").newDecoder().onMalformedInput(CodingErrorAction.REPLACE).onUnmappableCharacter(CodingErrorAction.REPLACE);
String urlDec = URLDecoder.decode("https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles%ef%bf%bc/", "UTF-8");
ByteBuffer buffer = ByteBuffer.wrap(urlDec.getBytes(Charset.forName("UTF-8")));
decoder.decode(buffer).toString();
Result
"https://www.breightgroup.com/job/hse-advisor-embedded-contract-roles/"
I found the issue resolved by just replacing URLs with this symbol because there are other URLs with Unicode symbols that were invisible that couldnt be converted ect..
So I just compared the urls to the following regex if it returns false then I just bypass it. Hope this helps someone out:
boolean newURL = url.matches("^[a-zA-Z0-9_:;/.&|%!+=#?-]*$");

Files.readAllLines() does not read all characters correctly

I have a simple text file which includes only one character which is '≤'. Nothing else. This file has UTF-8 encoding.
When I read this file using the method Files.readAllLines(), the character is shown as a question mark '?'
try (FileWriter fw = new FileWriter(new File(file, "f.txt"));
PrintWriter writer = new PrintWriter(fw);) {
List<String> lines = Files.readAllLines(deProp.toPath());
for (String line : lines) {
System.out.println(line);
writer.write(line);
writer.println();
}
In my example I am trying to print the line to the console and to a new file. In both cases a question mark is shown instead.
Any suggestions to solve this?
The Files.readAllLines(path) already uses UTF-8 (see the linked documentation). If you're using the Files.readAllLines(path, charset) variant, well, pass UTF-8 as the charset, of course (for example by using StandardCharsets.UTF_8).
Assuming you're using either the short version or passing UTF-8, then the error lies not with java, but with your setup.
Either the file doesn't contain ≤ in UTF-8, or you're printing it in java to a place that doesn't show such symbols (for example, because your font doesn't have it, and uses ? as the placeholder symbol for 'I do not have this symbol in my font file'; it's more usually a box symbol), or you're sending the output someplace that incorrectly presumes that what is sent is not UTF-8.
The static method of File class e.i
public static List<String> readAllLines(Path path) throws IOException
is read all the lines from a file. The bytes from the file are decoded into characters using the UTF-8 charset. This method invoking equivalent to evaluating the expression:
Files.readAllLines(path, StandardCharsets.UTF_8)
It may be possible that the file contains some garbage or something out of format of UTF-8 charset. Check the text inside files once manually :p

Can't use latin characters correctly when creating new files from within Java. Filenames get weird characters instead of the correct ones

Currently saving an int[] from hashmap in a file with the name of the key to the int[]. This exact key must be reachable from another program. Hence I can't switch name of the files to english only chars. But even though I use ISO_8859_1 as the charset for the filenames the files get all messed up in the file tree. The english letters are correct but not the special ones.
/**
* Save array to file
*/
public void saveStatus(){
try {
for(String currentKey : hmap.keySet()) {
byte[] currentKeyByteArray = currentKey.getBytes();
String bytesString = new String(currentKeyByteArray, StandardCharsets.ISO_8859_1);
String fileLocation = "/var/tmp/" + bytesString + ".dat";
FileOutputStream saveFile = new FileOutputStream(fileLocation);
ObjectOutputStream out = new ObjectOutputStream(saveFile);
out.writeObject(hmap.get(currentKey));
out.close();
saveFile.close();
System.out.println("Saved file at " + fileLocation);
}
} catch (IOException e) {
e.printStackTrace();
}
}
Could it have to do with how linux is encoding characters or is more likely to do with the Java code?
EDIT
I think the problem lies with the OS. Because when looking at text files with cat for example the problem is the same. However vim is able to decode the letters correctly. In that case I would have to perhaps change the language settings from the terminal?
You have to change the charset in the getBytes function as well.
currentKey.getBytes(StandardCharsets.ISO_8859_1);
Also, why are you using StandardCharsets.ISO_8859_1? To accept a wider range of characters, use StandardCharsets.UTF_8.
The valid characters of a filename or path vary depending on the file system used. While it should be possible to just use a java string as filename (as long as it does not contain characters invalid in the given file system), there might be interoperability issues and bugs.
In other words, leave out all Charset-magic as #RealSkeptic recommends and it should work. But changing the environment might result in unexpected behavior.
Depending on your requirements, you might therefore want to encode the key to make sure it only uses a reduced character set. One variant of Base64 might work (assuming your file system is case sensitive!). You might even find a library (Apache Commons?) offering a function to reduce a string to characters safe for use in a file name.

How do you reference a file in a path that has a space in it in Java?

I'm working on a project that involves reading a txt file, and the way I currently have it set up is with...
reader = new BufferedReader(new FileReader(new File(url)));
...where url is a String. I don't have it set up for the user to input their own file path (or my ultimate goal to be able to choose it in a window, but that's a different matter), so I Just have url set to something like...
"file:///C:/Users/Jeremiah/Desktop/generic_text_file.txt"
My problem is that, with this technique, I can't include spaces in the file path or I'll get an invalid character exception, yet most of files and directories on a computer that a person actually deals with has spaces in it, even ones that come on the computer like "My Documents".
I've also tried passing the String through a method to escape the spaces by adding "\" in front of them, but that still isn't working.
public String escapeSpaces(String string){
int cursor = 0;
System.out.println(string);
while(cursor<string.length()){
if(string.charAt(cursor)==' '){
string = string.substring(0,cursor)+"\\"+string.substring(cursor, string.length());
System.out.println(string);
cursor++;
}
cursor++;
}
return string;
}
So how would one get around this issue so that I could instead reference a file in say...
"file:///C:/Users/Jeremiah/Desktop/S O M A N Y S P A C E S/generic_text_file.txt"
Any feedback is appreciated.
You can't construct a File with a URl string. Just pass a proper filename string directly to the constructor of File, or indeed the constructor of FileReader. There is no issue with spaces in the filename.
it still doesn't allow me to use a file path with spaces
Yes it does. You are mistaken.
escaped or not
Filenames do not require escaping. URLS require escaping. But you're just making an unnecessary mess by using the URL class.

UTF-8 character encoding in Java

I am having some problems getting some French text to convert to UTF8 so that it can be displayed properly, either in a console, text file or in a GUI element.
The original string is
HANDICAP╔ES
which is supposed to be
HANDICAPÉES
Here is a code snippet that shows how I am using the jackcess Database driver to read in the Acccess MDB file in an Eclipse/Linux environment.
Database database = Database.open(new File(filepath));
Table table = database.getTable(tableName, true);
Iterator rowIter = table.iterator();
while (rowIter.hasNext()) {
Map<String, Object> row = this.rowIter.next();
// convert fields to UTF
Map<String, Object> rowUTF = new HashMap<String, Object>();
try {
for (String key : row.keySet()) {
Object o = row.get(key);
if (o != null) {
String valueCP850 = o.toString();
// String nameUTF8 = new String(valueCP850.getBytes("CP850"), "UTF8"); // does not work!
String valueISO = new String(valueCP850.getBytes("CP850"), "ISO-8859-1");
String valueUTF8 = new String(valueISO.getBytes(), "UTF-8"); // works!
rowUTF.put(key, valueUTF8);
}
}
} catch (UnsupportedEncodingException e) {
System.err.println("Encoding exception: " + e);
}
}
In the code you'll see where I want to convert directly to UTF8, which doesn't seem to work, so I have to do a double conversion. Also note that there doesn't seem to be a way to specify the encoding type when using the jackcess driver.
Thanks,
Cam
New analysis, based on new information.
It looks like your problem is with the encoding of the text before it was stored in the Access DB. It seems it had been encoded as ISO-8859-1 or windows-1252, but decoded as cp850, resulting in the string HANDICAP╔ES being stored in the DB.
Having correctly retrieved that string from the DB, you're now trying to reverse the original encoding error and recover the string as it should have been stored: HANDICAPÉES. And you're accomplishing that with this line:
String valueISO = new String(valueCP850.getBytes("CP850"), "ISO-8859-1");
getBytes("CP850") converts the character ╔ to the byte value 0xC9, and the String constructor decodes that according to ISO-8859-1, resulting in the character É. The next line:
String valueUTF8 = new String(valueISO.getBytes(), "UTF-8");
...does nothing. getBytes() encodes the string in the platform default encoding, which is UTF-8 on your Linux system. Then the String constructor decodes it with the same encoding. Delete that line and you should still get the same result.
More to the point, your attempt to create a "UTF-8 string" was misguided. You don't need to concern yourself with the encoding of Java's strings--they're always UTF-16. When bringing text into a Java app, you just need to make sure you decode it with the correct encoding.
And if my analysis is correct, your Access driver is decoding it correctly; the problem is at the other end, possibly before the DB even comes into the picture. That's what you need to fix, because that new String(getBytes()) hack can't be counted on to work in all cases.
Original analysis, based on no information. :-/
If you're seeing HANDICAP╔ES on the console, there's probably no problem. Given this code:
System.out.println("HANDICAPÉES");
The JVM converts the (Unicode) string to the platform default encoding, windows-1252, before sending it to the console. Then the console decodes that using its own default encoding, which happens to be cp850. So the console displays it wrong, but that's normal. If you want it to display correctly, you can change the console's encoding with this command:
CHCP 1252
To display the string in a GUI element, such as a JLabel, you don't have to do anything special. Just make sure you use a font that can display all the characters, but that shouldn't be problem for French.
As for writing to a file, just specify the desired encoding when you create the Writer:
OutputStreamWriter osw = new OutputStreamWriter(
new FileOutputStream("myFile.txt"), "UTF-8");
String s = "HANDICAP╔ES";
System.out.println(new String(s.getBytes("CP850"), "ISO-8859-1")); // HANDICAPÉES
This shows the correct string value. This means that it was originally encoded/decoded with ISO-8859-1 and then incorrectly encoded with CP850 (originally CP1252 a.k.a. Windows ANSI as pointed in a comment is indeed also possible since the É has the same codepoint there as in ISO-8859-1).
Align your environment and binary pipelines to use all the one and same character encoding. You can't and shouldn't convert between them. You would risk losing information in the non-ASCII range that way.
Note: do NOT use the above code snippet to "fix" the problem! That would not be the right solution.
Update: you are apparently still struggling with the problem. I'll repeat the important parts of the answer:
Align your environment and binary pipelines to use all the one and same character encoding.
You can not and should not convert between them. You would risk losing information in the non-ASCII range that way.
Do NOT use the above code snippet to "fix" the problem! That would not be the right solution.
To fix the problem you need to choose character encoding X which you'd like to use throughout the entire application. I suggest UTF-8. Update MS Access to use encoding X. Update your development environment to use encoding X. Update the java.io readers and writers in your code to use encoding X. Update your editor to read/write files with encoding X. Update the application's user interface to use encoding X. Do not use Y or Z or whatever at some step. If the characters are already corrupted in some datastore (MS Access, files, etc), then you need to fix it by manually replacing the characters right there in the datastore. Do not use Java for this.
If you're actually using the "command prompt" as user interface, then you're actually lost. It doesn't support UTF-8. As suggested in the comments and in the article linked in the comments, you need to create a Swing application instead of relying on the restricted command prompt environment.
You can specify encoding when establishing connection. This way was perfect and solve my encoding problem:
DatabaseImpl open = DatabaseImpl.open(new File("main.mdb"), true, null, Database.DEFAULT_AUTO_SYNC, java.nio.charset.Charset.availableCharsets().get("windows-1251"), null, null);
Table table = open.getTable("FolderInfo");
Using "ISO-8859-1" helped me deal with the French charactes.

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