List和数组的相互转换

1、将List转换为String数组

   List list = new ArrayList();
   list.add("1");
   list.add("2");
   final int size =　list.size();
   String[] arr = (String[])list.toArray(new String[size]);

2、将String数组转换为List

　String[] arr = new String[] {"1", "2"};

　List list = Arrays.asList(arr);