io流

 1         File file2 = new File("e:\\demo\\aa\\bb\\cc\\dd");
 2         file2.mkdirs();//多层
 3 
 4 
 5 
 6         for(int i = 1;i<=10;i++){
 7             
 8             File file = new File("e:\\demo\\demo"+i);
 9             file.mkdir();
10             for(int j = 0;j<=10;j++){
11                 File file1 = new File(file,"\\demo"+j+".txt");
12                 file1.createNewFile();
13             }
14         }

1         File file = new File("e:\\");
2         String [] s = file.list();
3         System.out.println(Arrays.toString(s));
4         for (String string : s) {
5             System.out.println(string);
6         }