list按对象属性排序

List<UserList> arr = new ArrayList<UserList>();
		arr.add(new UserList("Larry", "Rooney"));
		arr.add(new UserList("Marry", "Cooney"));
		arr.add(new UserList("Larry", "Cooney"));
		for (UserList ul : arr) {
			System.out.println("排序前lastname=" + ul.getLastname() + " firstname="
					+ ul.getFirstname());
		}
		Collections.sort(arr, new Comparator<UserList>() {
			
			public int compare(UserList u1, UserList u2) {
				int l = u1.getLastname().substring(0, 1).compareTo(
						u2.getLastname().substring(0, 1));
				if (l == 0) {
					return u1.getFirstname().substring(0, 1).compareTo(
							u2.getFirstname().substring(0, 1));
				}
				return l;
			}
		});
		for (UserList ul : arr) {
			System.out.println("排序后lastname=" + ul.getLastname() + " firstname="
					+ ul.getFirstname());
		}
	}