java使用iterator遍历指定目录示例分享

可以遍历指定目录（一个或多个）及其所有子文件，用iterator实现

package archiver.util;

import java.io.file;
import java.util.arraylist;
import java.util.arrays;
import java.util.iterator;
import java.util.list;

public class fileiterator implements iterator<file>, iterable<file> {
 private iterator<string> iterator;
 private list<string>  paths;
 private list<file>   dirs;

 public fileiterator(list<string> paths) {
  this.paths = new arraylist<string>(paths);
  this.dirs = new arraylist<file>();
  this.iterator = this.paths.iterator();
 }

 public file next() {
  file file = null;
  if (hasnext()) {
   file = new file(iterator.next());
   if (file.isdirectory()) {
    dirs.add(file);
   }
  }
  return file;
 }

 public boolean hasnext() {
  if (!iterator.hasnext()) {
   paths.clear();

   for (file dir : dirs) {
    for (string name : dir.list()) {
     paths.add(dir.getpath()+file.separator+name);
    }
   }
   dirs.clear();

   if (paths.size() == 0) {
    return false;
   }
   iterator = paths.iterator();
  }
  return true;
 }

 @override
 public void remove() {
  throw new unsupportedoperationexception();
 }

 @override
 public iterator<file> iterator() {
  return this;
 }

 public static void main(string[] args) {
  fileiterator iter = new fileiterator(arrays.aslist("."));
  for (file file : iter) {
   system.out.println(file);
  }
 }
}