JAVA I/O 非常实用的目录列表器

package com.file;

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Pattern;

public final class Directory {
	public static File[] local(File dir, final String regex) {
		return dir.listFiles(new FilenameFilter() {
			private Pattern pattern = Pattern.compile(regex);
			public boolean accept(File dir, String name) {
				return pattern.matcher(name).matches();
			}
		});
	}

	public static File[] local(String path, final String regex) {
		return local(new File(path), regex);
	}

	public static class TreeInfo implements Iterable<File> {
		public List<File> files = new ArrayList<File>();
		public List<File> dirs = new ArrayList<File>();

		public Iterator<File> iterator() {
			return files.iterator();
		}

		void addAll(TreeInfo other) {
			files.addAll(other.files);
			dirs.addAll(other.dirs);
		}

		public String toString() {
			return "dirs:" + PPrint.pformat(dirs) + "\n\nfiles:"
					+ PPrint.pformat(files);
		}

	}
	public static TreeInfo walk(String start, String regex) {
		return recurseDirs(new File(start), regex);
	}

	public static TreeInfo walk(String start) {
		return recurseDirs(new File(start), ".*");
	}

	public static TreeInfo walk(File start, String regex) {
		return recurseDirs(start, regex);
	}

	public static TreeInfo walk(File start) {
		return recurseDirs(start, ".*");
	}

	static TreeInfo recurseDirs(File startDir, String regex) {
		TreeInfo result = new TreeInfo();
		for (File item : startDir.listFiles()) {
			if (item.isDirectory()) {
				result.dirs.add(item);
				result.addAll(recurseDirs(item, regex));
			} else {
				if (item.getName().matches(regex))
					result.files.add(item);
			}
		}
		return result;
	}
	/**
	 * 调用方式
	 * @param args
	 */
	public static void main(String[] args) {
		System.out.println(local(".","D.*"));
		System.out.println(walk(".","D.*\\.java"));
		System.out.println(walk(".", "[Dd].*\\.*"));
		System.out.println(walk(".",".*\\.class"));
	}
}