JAVA chapter15. 컬렉션 프레임워크. 15.2 List 컬렉션

JAVA chapter15. 컬렉션 프레임워크. 15.2 List 컬렉션

package sec02.exam01_arraylist; import java.util.*; public class ArrayListExample { public static void main(String[] args) { List<String> list = new ArrayList<String>(); list.add("Java"); // 0 list.add("JDBC"); // 1 list.add("Servlet/JSP"); // 3 list.add(2, "Database"); // 2 list.add("iBATIS"); // 4 // 총 객체수 출력 int size = list.size(); System.out.println("총 객체수: " + size); System.out.println(); // 배열 출력 String skill = list.get(2); System.out.println("2: " + skill); System.out.println(); // 전체 출력 for(int i=0; i<list.size(); i++) { String str = list.get(i); System.out.println(i + ":" + str); } System.out.println(); // 삭제 list.remove(2); list.remove(2); list.remove("iBATIS"); // 출력 for(int i=0; i<list.size(); i++) { String str = list.get(i); System.out.println(i + ":" + str); } } }

package sec02.exam01_arraylist; import java.util.Arrays; import java.util.List; public class ArraysAsListExample { public static void main(String[] args) { List<String> list1 = Arrays.asList("홍길동", "신용권", "감자바"); for(String name: list1) { System.out.println(name); } List<Integer> list2 = Arrays.asList(1, 2, 3); // 자동 박싱 for(int value : list2) { // 자동 언박싱 System.out.println(value); } } }

15.2.2 Vector

package sec02.exam02_vector; import java.util.List; import java.util.Vector; public class VectorExample { public static void main(String[] args) { List<Board> list = new Vector<Board>(); list.add(new Board("제목1", "내용1", "글쓴이1")); list.add(new Board("제목2", "내용2", "글쓴이2")); list.add(new Board("제목3", "내용3", "글쓴이3")); list.add(new Board("제목4", "내용4", "글쓴이4")); list.add(new Board("제목5", "내용5", "글쓴이5")); list.remove(2); list.remove(3); for(int i=0; i<list.size(); i++) { Board board = list.get(i); System.out.println(board.subject + "\t" + board.content + "\t" + board.writer); } } }   package sec02.exam02_vector; public class Board { String subject; String content; String writer; public Board(String subject, String content, String writer) { this.subject = subject; this.content = content; this.writer = writer; } }

15.2.3 LinkedList

package sec02.exam03_linkedlist;
 
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
 
public class LinkedListExample {
    public static void main(String[] args) {
        List<String> list1 = new ArrayList<String>();
        List<String> list2 = new LinkedList<String>();
        
        long startTime;
        long endTime;
        
        startTime = System.nanoTime();
        for(int i=0; i<10000; i++) {
            list1.add(0, String.valueOf(i));
        }
        endTime = System.nanoTime();
        System.out.println("ArrayList 걸린시간: " + (endTime-startTime) + " ns");
        
        startTime = System.nanoTime();
        for(int i=0; i<10000; i++) {
            list2.add(0, String.valueOf(i));
        }
        endTime = System.nanoTime();
        System.out.println("LinkedList 걸린시간: " + (endTime-startTime) + " ns");
    }
}