【问题】

I have a text file with content like, with 792 lines:

der 17788648
und 14355959
die 10939606
Die 10480597

Now I want to compare if "Die" and "die" are equal in lowercase. So if two Strings in lowerCase are equal, copy the word into a new text file in lowerCase and sum the values.

Expected output:

der 17788648
und 14355959
die 21420203

I have that so far:

  try {
        BufferedReader bk = null;
        BufferedWriter bw = null;

        bk = new BufferedReader(new FileReader("outagain.txt"));
        bw = new BufferedWriter(new FileWriter("outagain5.txt"));

        List<String> list = new ArrayList<>();
        String s = "";
        while (s != null) {
            s = bk.readLine();
            list.add(s);
        }


        for (int k = 0; k < 793; k++) {
            String u = bk.readLine();
            if (list.contains(u.toLowerCase())) {

                //sum values?

            } else {
                bw.write(u + "\n");
            }
        }

        System.out.println(list.size());

    } catch (Exception e) {
        System.out.println("Exception caught : " + e);
    }

【回答】

       这是简单的分组汇总，JAVA没有通行的结构化计算类库，硬编码很繁琐。可以用SPL实现，只要一句。

A1：按第1个字段的小写分组，按第2个字段汇总。

A2：如果想把结果写到文件，可以再加此句。

这段代码可以方便地集成进Java，参考Java 如何调用 SPL 脚本。