关于java:Java-IO系统一

package javaio;
import java.io.File;
import java.io.FilenameFilter;
import java.util.Arrays;
import java.util.regex.Pattern;
public class DirList {public static void main(String[] args) {File path = new File(".");
        String[] list;
        if (args.length == 0) {list=path.list();
        }else
            list= path.list(new DirFilter(args[0]));
        Arrays.sort(list, String.CASE_INSENSITIVE_ORDER);
        for (String dirItem : list) {System.out.println(dirItem);
        }
    }
}
class DirFilter implements FilenameFilter {
    private Pattern pattern;
    public DirFilter(String regex) {this.pattern = Pattern.compile(regex);
    }
    @Override
    public boolean accept(File dir, String name) {return pattern.matcher(name).matches();}
}