keyset 后打印出特定值

Question

public static void main(String[] args) {
    HashMap<String, Integer>Car = new HashMap();
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter the number of employees worked with you this week");
    int Number = sc.nextInt();
    while (Number < 2 || Number > 5) {
        System.out.println("Enter a number between 2 and 5");
        Number = sc.nextInt();
    }
    System.out.println("Enter their names");
    String [] Name = new String [Number];
    sc.nextLine();
    for (int i=0; i<Number; i++) {
        int a = i+1;
        System.out.println("Enter name of employee " + a);
        Name[i] = sc.nextLine();
    }
    int[] Cars = new int[Number];
    for (int i=0; i<Number; i++) {
        String b = Name[i];
        System.out.println("Enter the number of cars sold by the employee " + b);
        Cars[i] = sc.nextInt();
        Car.put(Name[i], Cars[i]);
    }
    for (String i: Car.keySet()) {
        
    }
    ArrayList<Integer>CarOnly = new ArrayList<>(Car.values());
    Collections.sort(CarOnly, Collections.reverseOrder());
    for (int i: CarOnly) {
        for (String j: Car.keySet()) {
            if (i == Car.get(j))
                System.out.println(j);
        }
    }
    

}

}

我使这段代码用它的字符串显示最大值，但是，它没有打印出特定值，而是打印出 HashMap 中的整个值

Answer 1

我想这就是你想要达到的目标？

public class DumbCode {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        final HashMap<String, Integer> hashMap = new HashMap<>();

        System.out.println("Enter the number of employees working with you this week:");
        int numberOfEmployees = scanner.nextInt();
        while(numberOfEmployees<2 || numberOfEmployees>5) {
            numberOfEmployees = scanner.nextInt();
        }

        int i=0;
        while(i++<numberOfEmployees) {
            System.out.println("Enter the name:");
            final String name = scanner.next();
            System.out.println("Enter the number of cars sold");
            final int carsSold = scanner.nextInt();
            hashMap.put(name, carsSold);
        }

        hashMap.entrySet().stream()
                .sorted((o1, o2) -> o1.getValue() > o2.getValue() ? 1 : 0)
                .limit(1)
                .forEach(o -> {
                    System.out.println(o.getKey() + " sold "+ o.getValue()+" cars.");
                });
    }
}

但是，我也会为将来留下一些建议，在提问时，请明确您的目标是什么。 还要尝试编写更清晰的代码，例如，在尝试阅读代码时会出现很多问题。

1. 变量名称不应以大写字母开头，除非您要声明常量。
2. int Number = sc.nextInt(); 没有传达变量的意图。 int numberOfEmployees这个名字要好得多。
3. for (String i: Car.keySet()) { }如果什么都不做，把这个 for 循环有什么用？
4. 如果你想把东西存到一个HashMap中，那么你可以同时输入Key和Value直接放入，而不是用3个循环来填满一个HashMap。
5. 尝试使用函数式编程而不是命令式编程，因为它更具可读性和简洁性。

Answer 2

我从你的问题中了解到，你想显示在程序结束时售出最多汽车的员工的姓名。 如果是这种情况，请参阅下面的代码，我已经替换了您的一些代码以完成工作，请参阅代码中的注释以查找替换了哪部分代码：

public static void main(String[] args) {
HashMap<String, Integer>Car = new HashMap();
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of employees worked with you this week");
int Number = sc.nextInt();
while (Number < 2 || Number > 5) {
    System.out.println("Enter a number between 2 and 5");
    Number = sc.nextInt();
}
System.out.println("Enter their names");
String [] Name = new String [Number];
sc.nextLine();
for (int i=0; i<Number; i++) {
    int a = i+1;
    System.out.println("Enter name of employee " + a);
    Name[i] = sc.nextLine();
}
int[] Cars = new int[Number];
for (int i=0; i<Number; i++) {
    String b = Name[i];
    System.out.println("Enter the number of cars sold by the employee " + b);
    Cars[i] = sc.nextInt();
    Car.put(Name[i], Cars[i]);
}
for (String i: Car.keySet()) {
    
}
ArrayList<Integer>CarOnly = new ArrayList<>(Car.values());
Collections.sort(CarOnly, Collections.reverseOrder());


// i have replaced the code that is using nested loops with the code below
int maxCars = 0;
String maxEmployee = "";
for (String name : Car.keySet()) {
    int numCars = Car.get(name);
    if (numCars > maxCars) {
        maxCars = numCars;
        maxEmployee = name;
    }
}
System.out.println("The employee who sold the most cars is " + maxEmployee + " with " + maxCars + " cars sold.");

}

希望它有所帮助，请考虑阅读这篇文章我如何提出一个好问题？