Question

public class Test {
       public static void main(String[] args) {
        HashMap<String, City> cities = new HashMap<>();
        cities.put("Rome", new City("Rome", "Italy", 2869461));
        cities.put("Berlin", new City("Berlin", "Germany", 3610156));
        cities.put("Lisbon", new City("Lisbon", "Portugal", 545245));
        Iterator<String> keySetIterator = cities.keySet().iterator();
        System.out.println("HashMap has " + cities.size() + " elements");
        System.out.print("Enter a city to search for ");
        Scanner s = new Scanner(System.in);
        String searchtext = s.nextLine();
        System.out.println(searchtext);
        System.out.println("Key result " + cities.containsKey(searchtext));

        String key = keySetIterator.next();
            System.out.println("key: " + key + " value: " + cities.get(key).getName());
            if (cities.get(key).getName().contains(searchtext)) {
                      System.out.println("Value result found " + cities.get(key).getCountry() + " " + cities.get(key).getPopulation());
            }

我在main中有这个代码，我有一个只有getter，setter和constructor的类（City）。当我运行代码时，它仅在

时运行

searchtext = Rome

......如果我把

里斯本

代码没有插入最后的“if”，我也不知道为什么。有什么帮助吗？

Answer 1

Asimac，

看起来你只是用

获得了第一把钥匙

String key = keySetIterator.next();

我想你会想要检查所有条目而不是第一条。

考虑这样的事情：

while(keySetIterator.hasNext()){
        String key = keySetIterator.next();
        System.out.println("key: " + key + " value: " + cities.get(key).getName());
        if (cities.get(key).getName().contains(searchtext)) {
                  System.out.println("Value result found " + cities.get(key).getCountry() + " " + cities.get(key).getPopulation());
        }
}

将输入字符串与Hashmap中的多个键进行比较

1 个答案: