Question

I’m trying to sanitize a String that contains an uploaded file’s name. I’m doing this because the files will be downloaded from the web and, plus, I want to normalize the names. This is what I have so far:

private String pattern = "[^0-9_a-zA-Z\\(\\)\\%\\-\\.]";

//Class methods & stuff

private String sanitizeFileName(String badFileName) {
    StringBuffer cleanFileName = new StringBuffer();
    Pattern filePattern = Pattern.compile(pattern);
    Matcher fileMatcher = filePattern.matcher(badFileName);
    boolean match = fileMatcher.find();
    while(match) {
        fileMatcher.appendReplacement(cleanFileName, "");
        match = fileMatcher.find();
    }
    return cleanFileName.substring(0, cleanFileName.length() > 250 ? 250 : cleanFileName.length());         
}

This works ok, but for a strange reason the extension of the file is erased. i.e. “p%Z_-…#!$()=¡¿&+.jpg” ends up being “p%Z_-…()”.

Any Idea as to how should I tune up my regex?

Answer 1

You need a Matcher#appendTail at the end of your loop.