order string

输入是两个字符串（第一个字符串是自定义的字母顺序比如zafdbeg，第二个字符是任意输入的字符串），输出是按照第一个字符串的规则排好序的字符串

public static void main(String[] args) {
		String o1 = "adecbk";
		String i1 = "beckeda";
		System.out.println(outputAsOrder2(o1, i1));
	}

	public static String outputAsOrder2(String order, String input) {
		Map<Character, Integer> bucket = new HashMap<>();
		// 先记录input中每个字母的出现次数
		for (int i = 0; i < input.length(); ++i) {
			char c = input.charAt(i);
			Integer t = bucket.get(c);
			if (t == null)
				bucket.put(c, 1);
			else
				bucket.put(c, t + 1);
		}
		StringBuilder sb = new StringBuilder();
		// 把order中出现的字母都先排好序
		for (int i = 0; i < order.length(); ++i) {
			char c = order.charAt(i);
			Integer t = bucket.get(c);
			for (int j = 0; t != null && j < t; ++j) {
				sb.append(c);
			}
			bucket.remove(c);
		}
		// 把order中没出现，而input中剩下的字母提出来排序
		for (int i = 0; i < input.length(); ++i) {
			char c = input.charAt(i);
			if (bucket.containsKey(c))
				sb.append(c);
		}
		return sb.toString();
	}