HashTable 기본 실습

//HashTable 실습

//HashTable은 데이터를 넣을때 put을 사용 (키, 값)

//가져올땐 get

 

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import java.util.Collection;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.Set;

 

public class HashTableEx01 {

 

        public static void main(String[] args) {

               Hashtable<String, String> map = new Hashtable<String, String>();

              

               map.put("key1", "홍길동1");

               map.put("key2", "홍길동2");

               map.put("key3", "홍길동3");

              

               System.out.println(map.get("key1"));

               System.out.println(map.get("key2"));

               System.out.println(map.get("key3"));

              

               System.out.println("데이터의 갯수 : " + map.size());   //데이터 갯수

              

               //key값을 가져옴

               Enumeration<String> e = map.keys();

               while(e.hasMoreElements()){

                       System.out.println(e.nextElement());

               }

              

               Set<String> s = map.keySet();

               for(String key : s){

                       System.out.println(key);

               }

              

               //값 가져오기

               Collection<String> c = map.values();

               for(String value : c){

                       System.out.println(value);

               }

              

               for(String key : map.keySet()){

                       System.out.println(map.get(key));  //key를 이용해서 값을 보여줌

               }

              

              

        }

 

} 

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출력물

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홍길동1
홍길동2
홍길동3
데이터의 갯수 : 3
key3
key2
key1
key3
key2
key1
홍길동3
홍길동2
홍길동1
홍길동3
홍길동2
홍길동1 

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