Java 哈希表，带有 while 循环

Question

这就是我所需要的，也是我得到的。将数字 3 到 10 添加到散列 table 提示用户输入一个字符串，并显示相应的数字。使用循环和单个 println 语句，在 table 中显示所有值（字符串和整数）。我的主要问题是我不确定如何处理 while 循环。我只使用过一次 while 循环。

import java.util.*; 
class HTDemo {
    public static void main(String args[]) {
        Hashtable<String, Integer> numbers = new
                Hashtable<String, Integer>();

        numbers.put("one", new Integer(1));
        numbers.put("two", new Integer(2));
        numbers.put("three", new Integer(3));
        numbers.put("four", new Integer(4));
        numbers.put("five", new Integer(5));
        numbers.put("six", new Integer(6));
        numbers.put("seven", new Integer(7));
        numbers.put("eight", new Integer(8));
        numbers.put("nine", new Integer(9));
        numbers.put("ten", new Integer(10));

        String number;
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a number in word form: (Example: Five, Six,     Seven): ");
        number = input.next();
        while () {
            System.out.println("You entered: " + number + "\nwhich is the interger: " + numbers);
        }
    }
}

这是我得到的，与说明不符：

Enter a number in word form: (Example: Five, Six, Seven):
five
You entered: five
which is the integer: {three=3, six=6, ten=10, seven=7, nine=9, one=1, five=5, four=4, two=2, eight=8}

Answer 1

Scanner input = new Scanner(System.in); 
System.out.println("Enter a number in word form: (Example: Five, Six, Seven): "); 

// wait for input
String number = input.next(); 

// display value, using Map#get method
System.out.println(String.format("You've entered %s which is integer %s", number, numbers.get(number)));  

// iterate over map entries using for (not while) loop
for (Map.Entry<String, Integer> e : numbers.entrySet()) {
    System.out.println(String.format("Number:%s, integer:%s", e.getKey(), e.getValue())); 
}

顺便说一句，你不应该忘记字符串是区分大小写的，我。 e. numbers.get("Seven") 会 return null，因为你放的是 "seven"，而不是 "Seven"。

Java 哈希表，带有 while 循环

Java hashtable, with a while loop

java

hashtable

hashmap