20230628 _[19일차]_02. Excel을 자바로

3.

[Excel01.java]

[Excel02.java]

 

 

 

 

[Map01 & 02]

 

[ Treemap ]

package map;

import java.util.Map;
import java.util.TreeMap;

public class Map01 {
	public static void main(String[] args) {
		
		// treeMap : 이진트리를 기반으로 한 map
		
		TreeMap<Integer, String> map1 = new TreeMap<Integer, String>();
		map1.put(6, "자바");
		map1.put(3, "JSP");
		map1.put(7, "spring");
		map1.put(8, "SQL");
		map1.put(1, "Android");
		map1.put(9, "Swift");
		map1.put(5, "Python");
        
		System.out.println(map1);
		System.out.println(map1.keySet());
		System.out.println(map1.values());
		
	}
}

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{1=Android, 3=JSP, 5=Python, 6=자바, 7=spring, 8=SQL, 9=Swift}
[1, 3, 5, 6, 7, 8, 9]
[Android, JSP, Python, 자바, spring, SQL, Swift]

---

[ HashMap ]

package map;

import java.util.HashMap;
import java.util.Map;

public class Map02 {
	public static void main(String[] args) {
		
		HashMap<Integer, String> map02 = new HashMap<Integer, String>();
		
//		map02.put("5 번", "사과"); 	=> 키값이 문자면 정렬X
		map02.put(5, "사과");
		map02.put(6, "배");
		map02.put(1, "포도");
		map02.put(9, "복숭아");
		map02.put(7, "망고");
		map02.put(2, "두리안");

		System.out.println(map02);
		System.out.println(map02.keySet());
		
	}
}

---

{1=포도, 2=두리안, 5=사과, 6=배, 7=망고, 9=복숭아}
[1, 2, 5, 6, 7, 9]

 

 

* LinkedHashMap은 정렬안됨 *

 

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