java.io API : list method

Question

I am using java.io API's. There are lots of file in my dir for the below pattern.

    FilenameFilter fileFilter = new FilenameFilter() {
        public boolean accept(File dir, String name) {

            return name.matches(filePrefix+"_.*\\."+fileExt);

        }
    };

    String listFiles [] = dirFile.list(fileFilter);
       for(int i = 0 ;i < listFiles.length ; i++){
        listOfFiles.add(listFiles[i]);
        // need only 10 files to processed
        if(i == 10){
            break;
        }
    }

I wanted to know that list method will get listing based on what.I am if i wanted to have time based sorting, for example - if i want 10 files which are oldest /or latest.

How will i do it.

Solution :

Arrays.sort(listFiles, new Comparator<File>() {

        @Override
        public int compare(File f1, File f2) {
            return Long.valueOf(f1.lastModified()).compareTo(f2.lastModified());
        }
    });

Answer 1

The above only filters . You may be better off using the File.listFiles() method, which returns a set of File objects (you can provide an optional filter, as above). These objects will have the attributes that you want to further sort on (perhaps writing a custom Comparator ?). See the doc here and a sorting tutorial here .

Answer 2

您可以使用'listFiles(fileFilter)'列出文件对象而不是字符串，然后sort/filter它们进行sort/filter