Java Read file(s) with particular pattern

Question

I am trying to read files from unix file system with a pattern format in a java program.

The file name pattern is like this:

"XYZ"+"abcd1234"+MMddyyyyHHmmss

For example: XYZabc123403222012101329

The middle pattern of "abcd1234" is not fixed but changes, so it will be alphanumeric and total character length of 7.

How can I read the file with such pattern? The file can contain text or serialized object.

String path="/tmp/somedir";

final File folder = new File("/tmp/somedir");
List<String> fileNames = new ArrayList<String>();

    try {
        for (final File fileEntry : folder.listFiles()) {
            if (fileEntry.isDirectory()) {
                listFilesForFolder(fileEntry);
            } else {
                //System.out.println(fileEntry.getName());
                fileNames.add(fileEntry.getName());
            }
        }

        for(String str: fileNames) {
            FileInputStream fileIn = new FileInputStream(path+"/"+str);
        }

    } catch(FileNotFoundException e) {
        e.printStackTrace();
    } catch(Exception e1) {
        e1.printStackTrace();
    }

Thank You.

I think you want to look at making your own File filter, see: docs.oracle.com/javase/1.4.2/docs/api/java/io/… — David W
– David W, Commented Aug 22, 2012 at 18:55
You have to search the directory for a file which matches your requirements. — Peter Lawrey
– Peter Lawrey, Commented Aug 22, 2012 at 19:00

Community · Accepted Answer · 2017-05-23 11:56:15Z

2

I think you can use reguler expression for filtering files. Here is the class for doc for apache commons http://commons.apache.org/io/api-release/org/apache/commons/io/filefilter/RegexFileFilter.html and here is an old question about it. Java regexp for file filtering

edited May 23, 2017 at 11:56

CommunityBot

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answered Aug 22, 2012 at 19:05

Rifat Döver

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Comments

mj_ · Accepted Answer · 2012-08-22 19:05:18Z

0

You may be able to use a regular expression. I'm doing the exact same thing in C# right now. I have files that come from clients that have a common prefix, a date in the middle, and a common file extension.

Assuming that the abc1234 is always seven characters long, you could use the following regular expression pattern.

XYZ.{7}\d{14}

The .{7} means that any character can appear there up to seven times. The \d{14} means that it will count up to 14 digits.

answered Aug 22, 2012 at 19:05

mj_

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1 Comment

mj_ Over a year ago

You are welcome and thank you for thanking me. A lot of people certainly do not. Good luck with your project.

mtk · Accepted Answer · 2012-08-23 14:16:02Z

0

I recommend the this site, you'll find out how to get all the files from your directory.

After this, in the method : accept apply a regular expression on its parameter : name.

For regular expression, look toward this link.

edited Aug 23, 2012 at 14:16

mtk

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answered Aug 22, 2012 at 19:13

user1614620

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