AllMetanitLessons/Collections/equalsToStringHashCode/Prog.java - master - GermanezZ/JavaExercises

AllMetanitLessons/Collections/equalsToStringHashCode/Prog.java

78 строк2 KB

germa

Уроки по Metanit

04 дек 2024, 20:39

04 дек 2024, 20:3948d575a

package AllMetanitLessons.Collections.equalsToStringHashCode;


import java.util.*;

public class Prog{

    public static void main(String[] args) {

        Map<Integer,String> states = new HashMap<>();

        states.put(1,"Germany");
        states.put(2,"Spain");
        states.put(3,"France");
        states.put(4,"Italy");

        System.out.println(states.get(2));

        Set<Integer> keys = states.keySet();         // получим весь набор ключей
        Collection<String> values = states.values();  // получить набор всех значений

        System.out.println(keys);
        System.out.println("----------------------");
        System.out.println(values);
        System.out.println("-----------------------");

        states.replace(1,"Poland");     //заменить элемент


        states.remove(1);

        for (Map.Entry<Integer,String> item : states.entrySet()){
            System.out.printf("Key: %d\tValue: %s\n",item.getKey(),item.getValue());
        }


        System.out.println("-----------------------------------------------------");

        Map<String, Person> people = new HashMap<>();

        people.put("001A",new Person("Tom"));
        people.put("001B",new Person("Bill"));
        people.put("002A",new Person("Nick"));

        for (Map.Entry<String,Person> item : people.entrySet()){
            System.out.printf("Id: %s \t Name: %s\n", item.getKey(),item.getValue().getName());
        }



    }

}
class Person {

    private final String name;

    public Person(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Person person = (Person) o;
        return Objects.equals(name, person.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name);
    }
}