排序功能没有排序！JAVA

Question

下面是我用Java编写的测验程序中的代码块。我正在尝试将高分读取/写入文件，并对高分表进行排序

public static void main(String[] args) throws IOException {

        sort(highscoreTable);
        int score1 = 0;
        int score2 = 0;
        int totalscore = 0;
        int NumberofQuestions = 5;

        // RECORDS TO STORE QUESTION, ANSWER WOULD BE HERE //

private static void start(int NumberofQuestions, String[] Answers, String[][] questions, int score1, int score2, int totalscore) throws IOException {
        // DISPLAYED ON THE HOME SCREEN SO USER CAN CHOOSE WHAT THEY WANT TO DO
        System.out.println("[0] Leave\n");
        while(true) {
            System.out.println("[1] Play");
            System.out.println("[2] Highscore");
            System.out.print("Enter Choice: ");
            String useranswer = scanner.nextLine();
            System.out.println();
            if (useranswer.equals("1")) {
                mainLoop(NumberofQuestions, Answers, questions, score1, score2, totalscore);
            } else if (useranswer.equals("2")) {
                sort(highscoreTable);
            } else if (useranswer.equals("0")) {
                try {
                    save();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;
            }
        }
    }

我想先在屏幕上显示这个位，如果用户按2，我想编程读取文件并显示以前的高分

 public static void save() throws IOException {

        String aggFileName = "agg-"+String.valueOf("06.txt");
        FileWriter fstream = new FileWriter(aggFileName);
        BufferedWriter out = new BufferedWriter(fstream);

        for (Map.Entry<String, String> entry : highscoreTable.entrySet()) {
            System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue()); //this statement prints out my keys and values
            out.write(entry.getKey() + "--" + entry.getValue() + "\n");
            System.out.println("Done");
            out.flush();   // Flush the buffer and write all changes to the disk
        }

        out.close();    // Close the file
    }

save方法非常有效，我对它没有任何问题

public static void mainLoop(int NumberofQuestions, String[]Answers, String[][] questions, int score1, int score2, int totalscore) throws IOException {

// USER WOULD ANSWER QUESTIONS HERE
        addHighscore(name, totalscore);
    }

public static void addHighscore(String name, int totalscore) throws IOException {
        highscoreTable.put(String.valueOf(totalscore), name);
    }

这里的函数将用户名和总分添加到树状图中

public static void highscoreImport(HashMap highscoreTable) throws IOException {

        String filePath = "agg-06.txt";
        String line;
        BufferedReader reader = new BufferedReader(new FileReader(filePath));
        while ((line = reader.readLine()) != null)
        {
            String[] parts = line.split("--", 2);
            if (parts.length >= 2)
            {
                String key = parts[0];
                String value = parts[1];
                highscoreTable.put(key, value);
            } else {
            }
        }
        for (Object key : highscoreTable.keySet())
        {
            System.out.println(key + "--" + highscoreTable.get(key));
        }

        reader.close();

    }

这是我遇到问题的部分。我希望程序从文件中获取信息，现在将其与来自用户最近测验的数据合并，然后对分数进行排序（我想要一个高分表），这样当用户键入“2”以查看高分表时，它将按降序排列

public static void sort(HashMap highscoreTable) throws IOException {

        System.out.println("Before Sorting:");
        Set set = highscoreTable.entrySet();
        Iterator iterator = set.iterator();
        while(iterator.hasNext()) {
            Map.Entry me = (Map.Entry)iterator.next();
            System.out.print(me.getKey() + ": ");
            System.out.println(me.getValue());
        }
        Map<Integer, String> map = new TreeMap<Integer, String>(highscoreTable);
        System.out.println("After Sorting:");
        Set set2 = map.entrySet();
        Iterator iterator2 = set2.iterator();
        while(iterator2.hasNext()) {
            Map.Entry me2 = (Map.Entry)iterator2.next();
            System.out.print(me2.getKey() + ": ");
            System.out.println(me2.getValue());
        }
    }

这里，“之前”和“之后”排序输出的列表是相同的未排序列表

---

很抱歉读了这么长时间，如果有人能帮我解决这个问题，我将不胜感激

Answer 1

因为在addHighscore方法中，您正在执行以下操作：

highscoreTable.put(String.valueOf(totalscore), name);

我假设它是Map<String, String>（键和值类型都是String）

但是在sort方法中，您确实

Map<Integer, String> map = new TreeMap<Integer, String>(highscoreTable);

如果正确定义了highscoreTable的类型，则TreeMap实例化在编译时应该失败。如果不是，并且构造函数TreeMap(Map)按照其键的自然顺序进行排序（参见Javadoc），它可能是按照String顺序或其他顺序对其进行排序。所以“111”之前会出现“12”等意想不到的结果。最好在所有集合和其他泛型类型类中定义类型

Answer 2

问题在于分数的类型。您正在将分数作为字符串插入。第二个小问题是排序顺序应该颠倒

请看以下示例：

public class Test {

public static void main(String[] args) throws IOException {
    System.out.println("String scores:");
    HashMap<String, String> scores = new HashMap<>();
    scores.put("12", "John");
    scores.put("240", "Mary");
    scores.put("14", "Sean");
    scores.put("35", "Pat");

    sort(scores);
    System.out.println();

    System.out.println("Integer scores:");
    HashMap<Integer,String> integerScores = new HashMap<>();
    integerScores.put(12, "John");
    integerScores.put(240, "Mary");
    integerScores.put(14, "Sean");
    integerScores.put(35, "Pat");

    sort(integerScores);
}

public static void sort(HashMap highscoreTable) throws IOException {

    System.out.println("Before Sorting:");
    Set set = highscoreTable.entrySet();
    Iterator iterator = set.iterator();
    while(iterator.hasNext()) {
        Map.Entry me = (Map.Entry)iterator.next();
        System.out.print(me.getKey() + ": ");
        System.out.println(me.getValue());
    }
    Map<Integer, String> map = new TreeMap<Integer, String>(Collections.reverseOrder());    // Descending
    map.putAll(highscoreTable);
    System.out.println("After Sorting:");
    Set set2 = map.entrySet();
    Iterator iterator2 = set2.iterator();
    while(iterator2.hasNext()) {
        Map.Entry me2 = (Map.Entry)iterator2.next();
        System.out.print(me2.getKey() + ": ");
        System.out.println(me2.getValue());
    }
}

}

本例使用“分数”和“整数核心”的排序方法。 以下是排序后的输出： 字符串分数： 35:Pat 240:玛丽 14:Sean 12:John

整数分： 240:玛丽 35:Pat 14:Sean 12:John

你可以在第一类中看到35在240之前，因为3在2之前。它正在进行字符串排序。第二种排序是按整数的值排序。一旦理解了这一点，就很容易修复代码

原始代码将键作为字符串插入：

highscoreTable.put(key, value);

键应为整数：

highscoreTable.put(Integer.valueOf(key), value);

还请注意，提供的答案可以轻松运行。它包括数据（比附加文件更简单）和输出。当问题以这种方式格式化时，更容易获得帮助