字符串，按一定长度分割

public List<String> getStrList(String inputString, int length) {
		int size = inputString.length() / length;
		if (inputString.length() % length != 0) {
			size += 1;
		}
		return getStr(inputString, length, size);
	}

	public List<String> getStr(String inputString, int length, int size) {
		List<String> list = new ArrayList<String>();
		for (int index = 0; index < size; index++) {
			String str = substring(inputString, index * length, (index + 1) * length);
			list.add(str);
		}
		return list;

	}

	public String substring(String str, int f, int t) {
		if (f > str.length()) {
			return null;
		}
		if (t > str.length()) {
			return str.substring(f, str.length());
		} else {
			return str.substring(f, t);
		}
	}