How to find files that match a wildcard string in Java?

user_44330 0
Viewed 296112

This should be really simple. If I have a String like this:

../Test?/sample*.txt

then what is a generally-accepted way to get a list of files that match this pattern? (e.g. it should match ../Test1/sample22b.txt and ../Test4/sample-spiffy.txt but not ../Test3/sample2.blah or ../Test44/sample2.txt)

I've taken a look at org.apache.commons.io.filefilter.WildcardFileFilter and it seems like the right beast but I'm not sure how to use it for finding files in a relative directory path.

I suppose I can look the source for ant since it uses wildcard syntax, but I must be missing something pretty obvious here.

(edit: the above example was just a sample case. I'm looking for the way to parse general paths containing wildcards at runtime. I figured out how to do it based on mmyers' suggestion but it's kind of annoying. Not to mention that the java JRE seems to auto-parse simple wildcards in the main(String[] arguments) from a single argument to "save" me time and hassle... I'm just glad I didn't have non-file arguments in the mix.)

wildcard file java
17 Answers

Try FileUtils from Apache commons-io (listFiles and iterateFiles methods):

File dir = new File(".");
FileFilter fileFilter = new WildcardFileFilter("sample*.java");
File[] files = dir.listFiles(fileFilter);
for (int i = 0; i < files.length; i++) {
   System.out.println(files[i]);
}

To solve your issue with the TestX folders, I would first iterate through the list of folders:

File[] dirs = new File(".").listFiles(new WildcardFileFilter("Test*.java");
for (int i=0; i<dirs.length; i++) {
   File dir = dirs[i];
   if (dir.isDirectory()) {
       File[] files = dir.listFiles(new WildcardFileFilter("sample*.java"));
   }
}

Quite a 'brute force' solution but should work fine. If this doesn't fit your needs, you can always use the RegexFileFilter.

Vladimir_96410

Consider DirectoryScanner from Apache Ant:

DirectoryScanner scanner = new DirectoryScanner();
scanner.setIncludes(new String[]{"**/*.java"});
scanner.setBasedir("C:/Temp");
scanner.setCaseSensitive(false);
scanner.scan();
String[] files = scanner.getIncludedFiles();

You'll need to reference ant.jar (~ 1.3 MB for ant 1.7.1).

Misha_75570

You could convert your wildcard string to a regular expression and use that with String's matches method. Following your example:

String original = "../Test?/sample*.txt";
String regex = original.replace("?", ".?").replace("*", ".*?");

This works for your examples:

Assert.assertTrue("../Test1/sample22b.txt".matches(regex));
Assert.assertTrue("../Test4/sample-spiffy.txt".matches(regex));

And counter-examples:

Assert.assertTrue(!"../Test3/sample2.blah".matches(regex));
Assert.assertTrue(!"../Test44/sample2.txt".matches(regex));
Fabian_Steeg_181540

Might not help you right now, but JDK 7 is intended to have glob and regex file name matching as part of "More NIO Features".

Tom_Hawtin_-_tackline_47250

The wildcard library efficiently does both glob and regex filename matching:

http://code.google.com/p/wildcard/

The implementation is succinct -- JAR is only 12.9 kilobytes.

user_1878830

The Apache filter is built for iterating files in a known directory. To allow wildcards in the directory also, you would have to split the path on '\' or '/' and do a filter on each part separately.

user_135310

Using Java streams only

Path testPath = Paths.get("C:\");

Stream<Path> stream =
                Files.find(testPath, 1,
                        (path, basicFileAttributes) -> {
                            File file = path.toFile();
                            return file.getName().endsWith(".java");
                        });

// Print all files found
stream.forEach(System.out::println);
user_13873860

Why not use do something like:

File myRelativeDir = new File("../../foo");
String fullPath = myRelativeDir.getCanonicalPath();
Sting wildCard = fullPath + File.separator + "*.txt";

// now you have a fully qualified path

Then you won't have to worry about relative paths and can do your wildcarding as needed.

Elijah_336110

The most simple and easy way by using the io library's File class would be :

    String startingdir="The directory name";
    String filenameprefix="The file pattern"
    File startingDirFile=new File(startingdir); 
    final File[] listFiles=startingDirFile.listFiles(new FilenameFilter() {
        public boolean accept(File arg0,String arg1)
        {System.out.println(arg0+arg1);
            return arg1.matches(filenameprefix);}
        });
    System.out.println(Arrays.toString(listFiles));
user_137994830
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