[JAVA/수업 과제 practice] 클래스와 객체 Lv. 1~2

✅ 답안과 비교하여 스스로 코드 개선점 짚어보기 완료(2022.01.03)

 

NORMAL2. 모든 필드를 초기화하는 생성자 활용 ✅

printInformation 메소드에서 변수를 this.grade가 아닌 그냥 grade로 쓴다. 어차피 가리키는 값은 전역변수 grade이기 때문이다.

int 다음 String을 스캔 받는 경우 등에는 개행을 위해 입력 받을 값 앞에 scanner.nextLine();를 쓴다.

학년 : 1
반 : 2
이름 : 김자바
키 : 160.5
성별 : 여

package com.greedy.level02.normal.student.dto;

public class StudentDTO {

	private int grade;
	private int classroom;
	private String name;
	private double height;
	private char gender;
	
	public StudentDTO() {
		
	}
	
	public StudentDTO(int grade, int classroom, String name, double height, char gender) {
		this.grade = grade;
		this.classroom = classroom;
		this.name = name;
		this.height = height;
		this.gender = gender;
	}
	
	/* 설정자(setter) 메소드 */
	public void setGrade(int grade) {
		this.grade = grade;
	}
	public void setClassroom(int classroom) {
		this.classroom = classroom;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setHeight(double height) {
		this.height = height;
	}
	public void setGender(char gender) {
		this.gender = gender;
	}
	
	/* 접근자(getter) 메소드 */
	public int getGrade() {
		return grade;
	}
	public int getClassroom() {
		return classroom;
	}
	public String getName() {
		return name;
	}
	public double getHeight() {
		return height;
	}
	public char getGender() {
		return gender;
	}
	
	public void printInformation() {
		System.out.println("학년 : " + grade);
		System.out.println("반 : " + classroom);
		System.out.println("이름 : " + name);
		System.out.println("키 : " + height);
		System.out.println("성별 : " + gender);
	}	
}

package com.greedy.level02.normal.student.run;

import java.util.Scanner;

import com.greedy.level02.normal.student.dto.StudentDTO;

public class Application {

	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		System.out.print("학년 : ");
		int grade = scanner.nextInt();
		
		System.out.print("반 : ");
		int classroom = scanner.nextInt();
		
		System.out.print("이름 : ");
		scanner.nextLine();
        String name = scanner.nextLine();
		
		System.out.print("키 : ");
		double height = scanner.nextDouble();
		
		System.out.print("성별 : ");
		char gender = scanner.next().charAt(0);
		
		StudentDTO student = new StudentDTO(grade, classroom, name, height, gender);
		student.printInformation();
	}

}

 

NORMAL1. 기본 생성자부터 모든 필드를 초기화하는 생성자 통해 출력하기 ✅

함수 호출하여 출력할 때 System.out.println();에 담지 않고 사용한다.

null, null, null, 0, 0.0
자바의 정석, 도우출판, 남궁성, 0, 0.0
홍길동전, 활빈당, 허균, 5000000, 0.5

package com.greedy.level02.normal.book.model.dto;

public class BookDTO {
	
	private String title;
	private String publisher;
	private String author;
	private int price;
	private double discountRate;
	
	public BookDTO() {
		
	}
	
	public BookDTO(String title, String publisher, String author) {
		this.title = title;
		this.publisher = publisher;
		this.author = author;
	}
	
	public BookDTO(String title, String publisher, String author, int price, double discountRate) {
		this(title, publisher, author);
		this.price = price;
		this.discountRate = discountRate;
	}
	
	/* 설정자(setter) 메소드 */
	public void setTitle(String title) {
		this.title = title;
	}
	public void setPublisher(String publisher) {
		this.publisher = publisher;
	}
	public void setAuthor(String author) {
		this.author = author;
	}
	public void setPrice(int price) {
		this.price = price;
	}
	public void setDiscountRate(double discountRate) {
		this.discountRate = discountRate;
	}
	
	/* 접근자(getter) 메소드 */
	public String getTitle() {
		return title;
	}
	public String getPublisher() {
		return publisher;
	}
	public String getAuthor() {
		return author;
	}
	public int getPrice() {
		return price;
	}
	public double getDiscountRate() {
		return discountRate;
	}
	
	/* 출력 메소드 */
	public String getInformation() {
		return this.title + ", " + this.publisher + ", " + this.author + ", " + this.price + ", " + this.discountRate;
	}

}

package com.greedy.level02.normal.book.run;

import com.greedy.level02.normal.book.model.dto.BookDTO;

public class Application {

	public static void main(String[] args) {
		
		BookDTO book1 = new BookDTO();
		book1.getInformation();
		
		BookDTO book2 = new BookDTO("자바의 정석", "도우출판", "남궁성");
		book2.getInformation();
		
		BookDTO book3 = new BookDTO("홍길동전", "활빈당", "허균", 5000000, 0.5);
		book3.getInformation();

	}

}

 

BASIC1. 설정자(setter)와 접근자(getter) 활용 ✅

순서대로 getter를 이용한 초기값 확인, setter를 이용한 필드값 변경, getter를 이용하여 변경된 초기값 확인까지 이어진다.

id : null
pwd : null
name : null
age : 0
gender : 
phone : null
email : null
변경 후 id : user01
변경 후 pwd : pass01
변경 후 name : 홍길동
변경 후 age : 20
변경 후 gender : M
변경 후 phone : 010-1234-5678
변경 후 email : hong123@greedy.com

package com.greedy.level01.basic.member.model.dto;

public class MemberDTO {
	
	private String id;
	private String pwd;
	private String name;
	private int age;
	private char gender;
	private String phone;
	private String email;
	
	/* 설정자(setter) 메소드 */
	public void setId(String id) {
		this.id = id;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public void setGender(char gender) {
		this.gender = gender;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	
	/* 접근자(getter) 메소드 */
	public String getId() {
		return id;
	}
	public String getPwd() {
		return pwd;
	}
	public String getName() {
		return name;
	}
	public int getAge() {
		return age;
	}
	public char getGender() {
		return gender;
	}
	public String getPhone() {
		return phone;
	}
	public String getEmail() {
		return email;
	}

}

package com.greedy.level01.basic.member.run;

import com.greedy.level01.basic.member.model.dto.MemberDTO;

public class Application {

	public static void main(String[] args) {
		
		MemberDTO member = new MemberDTO();
		
		System.out.println("id : " + member.getId());
		System.out.println("pwd : " + member.getPwd());
		System.out.println("name : " + member.getName());
		System.out.println("age : " + member.getAge());
		System.out.println("gender : " + member.getGender());
		System.out.println("phone : " + member.getPhone());
		System.out.println("email : " + member.getEmail());
		
		member.setId("user01");
		member.setPwd("pass01");
		member.setName("홍길동");
		member.setAge(20);
		member.setGender('M');
		member.setPhone("010-1234-5678");
		member.setEmail("hong123@greedy.com");
		
		System.out.println("변경 후 id : " + member.getId());
		System.out.println("변경 후 pwd : " + member.getPwd());
		System.out.println("변경 후 name : " + member.getName());
		System.out.println("변경 후 age : " + member.getAge());
		System.out.println("변경 후 gender : " + member.getGender());
		System.out.println("변경 후 phone : " + member.getPhone());
		System.out.println("변경 후 email : " + member.getEmail());
	}

}