java - 将逗号分隔的字符串转换为 HashSet

Question

那么，您将如何进行转换

String csv = "11,00,33,66,44,33,22,00,11";

以最快最优化的方式到哈希集。

这是一个用户 ID 列表。

更新

我运行了一个测试程序提供的所有答案，其中每个方法都被调用了 500,000 次以获得更大的 CSV 字符串。该测试连续执行了 5 次(以防程序启动减慢初始方法)，我得到了以毫秒 (ms) 为单位的以下结果:

Method One Liner->  6597
Method Split&Iterate->  6090
Method Tokenizer->  4306
------------------------------------------------
Method One Liner->  6321
Method Split&Iterate->  6012
Method Tokenizer->  4227
------------------------------------------------
Method One Liner->  6375
Method Split&Iterate->  5986
Method Tokenizer->  4340
------------------------------------------------
Method One Liner->  6283
Method Split&Iterate->  5974
Method Tokenizer->  4302
------------------------------------------------
Method One Liner->  6343
Method Split&Iterate->  5920
Method Tokenizer->  4227
------------------------------------------------


static void method0_oneLiner() {
        for (int j = 0; j < TEST_TIMES; j++) {
            Set<String> hashSet = new HashSet<String>(Arrays.asList(csv
                    .split(",")));
        }
    }

    // ———————————————————————————————–

    static void method1_splitAndIterate() {

        for (int j = 0; j < TEST_TIMES; j++) {
            String[] values = csv.split(",");
            HashSet<String> hSet = new HashSet<String>(values.length);
            for (int i = 0; i < values.length; i++)
                hSet.add(values[i]);
        }
    }

    static void method2_tokenizer() {

        for (int j = 0; j < TEST_TIMES; j++) {
            HashSet<String> hSet = new HashSet<String>();
            StringTokenizer st = new StringTokenizer(csv, ",");
            while (st.hasMoreTokens())
                hSet.add(st.nextToken());
        }
    }

Answer 1

String[] values = csv.split(",");
Set<String> hashSet = new HashSet<String>(Arrays.asList(values));