Java Hashtable 생성 및 초기화하는 방법 6가지

Java의 Hashtable은 동기화된 Map 인터페이스의 구현체입니다. 이 글에서는 여러 가지 방법으로 Hashtable을 생성하고 초기화하는 예제들을 소개하겠습니다.

 

 

예제 1. 기본 생성 및 초기화

import java.util.Hashtable;
import java.util.Map;

public class HashtableExample {
    public static void main(String[] args) {
        Map<String, Integer> hashtable = new Hashtable<>();

        hashtable.put("one", 1);
        hashtable.put("two", 2);
        hashtable.put("three", 3);

        System.out.println(hashtable);
    }
}

 

 

 

예제 2. 생성 시 초기 용량 지정

import java.util.Hashtable;
import java.util.Map;

public class HashtableExample {
    public static void main(String[] args) {
        Map<String, Integer> hashtable = new Hashtable<>(5);

        hashtable.put("one", 1);
        hashtable.put("two", 2);
        hashtable.put("three", 3);

        System.out.println(hashtable);
    }
}

 

 

 

예제 3. 생성 시 초기 용량 및 로드 팩터 지정

import java.util.Hashtable;
import java.util.Map;

public class HashtableExample {
    public static void main(String[] args) {
        Map<String, Integer> hashtable = new Hashtable<>(5, 0.75f);

        hashtable.put("one", 1);
        hashtable.put("two", 2);
        hashtable.put("three", 3);

        System.out.println(hashtable);
    }
}

 

 

 

예제 4. 익명 클래스를 사용한 초기화

import java.util.Hashtable;
import java.util.Map;

public class HashtableExample {
    public static void main(String[] args) {
        Map<String, Integer> hashtable = new Hashtable<String, Integer>() {{
            put("one", 1);
            put("two", 2);
            put("three", 3);
        }};

        System.out.println(hashtable);
    }
}

 

 

 

예제 5. Java 8의 Stream API를 사용한 초기화

import java.util.Hashtable;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class HashtableExample {
    public static void main(String[] args) {
        Map<String, Integer> hashtable = Stream.of(new Object[][]{
                {"one", 1},
                {"two", 2},
                {"three", 3},
        }).collect(Collectors.toMap(data -> (String) data[0], data -> (Integer) data[1], (v1, v2) -> v2, Hashtable::new));

        System.out.println(hashtable);
    }
}

이 글에서 소개한 예제들은 다양한 방법으로 Hashtable을 생성하고 초기화하는 방법을 보여줍니다. 상황에 따라 적절한 방법을 선택하여 사용할 수 있습니다.