[자바] 멀티미디어자바프로젝트II ch.06 연습문제

예외처리를 하여 프로그램이 종료되지 않고 이어지도록 작동하도록 하는 의도로 예외처리를 한다.

package _1020_A;
import java.util.Scanner;
 
public class Main {
    
    public static Scanner keyboard=new Scanner(System.in);
 
    public static void main(String[] args) {
        String input;
        
        while(true)
        {
            System.out.print("입력하시오(종료:Z) ");
            input = keyboard.nextLine();
            if(input.equals("Z"))
            {
                System.out.println("프로그램을 종료합니다!!");
                return;
            }
            
            try
            {
                Integer.parseInt(input);
                System.out.println("숫자입니다!!");
            }
            catch (Exception e)
            {
                System.out.println("문자입니다!!");
            }
            
        }        
    }
}
 

Java Custom Exception - javatpoint

 

 

package _1020_B;
/*
 * 전화번호 관리 프로그램 구현 프로젝트
 * Version 0.5
 */
 
import java.util.Scanner;
 
interface INIT_MENU
{
    int INPUT=1, SEARCH=2, DELETE=3, EXIT=4;
}
 
interface INPUT_SELECT
{
    int NORMAL=1, UNIV=2, COMPANY=3;
}
 
class PhoneInfo
{
    String name;
    String phoneNumber;
    
    public PhoneInfo(String name, String num)
    {
        this.name=name;
        phoneNumber=num;
    }
    
    public void showPhoneInfo()
    {
        System.out.println("name: "+name);
        System.out.println("phone: "+phoneNumber);
    }
}
 
class PhoneUnivInfo extends PhoneInfo
{
    String major;
    int year;    
    
    public PhoneUnivInfo(String name, String num, String major, int year)
    {
        super(name, num);
        this.major=major;
        this.year=year;
    }
    
    public void showPhoneInfo()
    {
        super.showPhoneInfo();
        System.out.println("major: "+major);
        System.out.println("year: "+year);
    }
}
 
class PhoneCompanyInfo extends PhoneInfo
{
    String company;
    
    public PhoneCompanyInfo(String name, String num, String company)
    {
        super(name, num);
        this.company=company;
    }
    
    public void showPhoneInfo()
    {
        super.showPhoneInfo();
        System.out.println("company: "+company);
    }
}
 
class PhoneBookManager
{
    final int MAX_CNT=100;
    PhoneInfo[] infoStorage=new PhoneInfo[MAX_CNT];
    int curCnt=0;
    
    static PhoneBookManager inst=null;
    public static PhoneBookManager createManagerInst()
    {
        if(inst==null)
            inst=new PhoneBookManager();
        
        return inst;
    }
    
    private PhoneBookManager(){}
    
    private PhoneInfo readFriendInfo()
    {
        System.out.print("이름: ");
        String name=MenuViewer.keyboard.nextLine();
        System.out.print("전화번호: ");
        String phone=MenuViewer.keyboard.nextLine();
        return new PhoneInfo(name, phone);
    }
    
    private PhoneInfo readUnivFriendInfo()
    {
        System.out.print("이름: ");
        String name=MenuViewer.keyboard.nextLine();
        System.out.print("전화번호: ");
        String phone=MenuViewer.keyboard.nextLine();
        System.out.print("전공: ");
        String major=MenuViewer.keyboard.nextLine();
        System.out.print("학년: ");
        int year=MenuViewer.keyboard.nextInt();
        MenuViewer.keyboard.nextLine();
        return new PhoneUnivInfo(name, phone, major, year);
    }
    
    private PhoneInfo readCompanyFriendInfo()
    {
        System.out.print("이름: ");
        String name=MenuViewer.keyboard.nextLine();
        System.out.print("전화번호: ");
        String phone=MenuViewer.keyboard.nextLine();
        System.out.print("회사: ");
        String company=MenuViewer.keyboard.nextLine();
        return new PhoneCompanyInfo(name, phone, company);    
    }    
    
    public void inputData() throws InputException
    {
        System.out.println("데이터 입력을 시작합니다..");
        System.out.println("1. 일반, 2. 대학, 3. 회사");
        System.out.print("선택>> ");
        int choice=MenuViewer.keyboard.nextInt();
        MenuViewer.keyboard.nextLine();
        
        if(choice > 3 || choice < 1) 
        {
            throw new InputException(choice);
        }
        
        PhoneInfo info=null;
        
        switch(choice)
        {
        case INPUT_SELECT.NORMAL:
            info=readFriendInfo();
            break;
        case INPUT_SELECT.UNIV:
            info=readUnivFriendInfo();
            break;
        case INPUT_SELECT.COMPANY:
            info=readCompanyFriendInfo();
            break;
        }
        
        infoStorage[curCnt++]=info;
        System.out.println("데이터 입력이 완료되었습니다. \n");        
    }
    
    public void searchData()
    {
        System.out.println("데이터 검색을 시작합니다..");
        
        System.out.print("이름: ");
        String name=MenuViewer.keyboard.nextLine();
        
        int dataIdx=search(name);
        if(dataIdx<0)
        {
            System.out.println("해당하는 데이터가 존재하지 않습니다. \n");
        }
        else
        {
            infoStorage[dataIdx].showPhoneInfo();
            System.out.println("데이터 검색이 완료되었습니다. \n");
        }
    }
    
    public void deleteData()
    {
        System.out.println("데이터 삭제를 시작합니다..");
        
        System.out.print("이름: ");
        String name=MenuViewer.keyboard.nextLine();
        
        int dataIdx=search(name);
        if(dataIdx<0)
        {
            System.out.println("해당하는 데이터가 존재하지 않습니다. \n");
        }
        else
        {
            for(int idx=dataIdx; idx<(curCnt-1); idx++)
                infoStorage[idx]=infoStorage[idx+1];
            
            curCnt--;
            System.out.println("데이터 삭제가 완료되었습니다. \n");
        }
    }
    
    private int search(String name)
    {
        for(int idx=0; idx<curCnt; idx++)
        {
            PhoneInfo curInfo=infoStorage[idx];
            if(name.compareTo(curInfo.name)==0)
                return idx;
        }
        return -1;
    }
}
 
 
 
class MenuViewer
{
    public static Scanner keyboard=new Scanner(System.in);
    
    public static void showMenu()
    {
        System.out.println("선택하세요...");
        System.out.println("1. 데이터 입력");
        System.out.println("2. 데이터 검색");
        System.out.println("3. 데이터 삭제");
        System.out.println("4. 프로그램 종료");
        System.out.print("선택: ");
    }
}
 
class Main
{    
    public static void main(String[] args)
    {
        //Untitled From Jackdclee
        //https://pastebin.com/DXgRBJG4
        
        //PhoneBookManager은 createManagerInst()함수를 통한 인스턴스 생성만 가능하게 구현(싱글톤 패턴을 이용하기 위해)
        //PhoneBookManager manager=PhoneBookManager.createManagerInst();
        
        //PhoneBookManager를 담는 변수를 3개 만들고, 변수(레퍼런스)는 3개이지만 PhoneBookManager.createManagerInst();
        //싱글톤 패턴을 적용한 클래스이기에 실제로는 하나의 인스턴스에 대한 레퍼런스는 동일하다.
        PhoneBookManager manager1=PhoneBookManager.createManagerInst();
        PhoneBookManager manager2=PhoneBookManager.createManagerInst();
        PhoneBookManager manager3=PhoneBookManager.createManagerInst();
        
        //생성자가 Private로 되어있어 생성자를 통한 인스턴스 생성이 불가
        //PhoneBookManager managerInst2 = new PhoneBookManager();
        
        int choice;
        
        while(true)
        {
            MenuViewer.showMenu();
            choice=MenuViewer.keyboard.nextInt();
            
            MenuViewer.keyboard.nextLine();
            
            try
            {
                if(choice > 4 || choice < 1) 
                {
                    throw new InputException(choice);                                    
                }
            }
            catch (InputException e)
            {
                e.printStackTrace();
            }
            
            
            switch(choice)
            {
            case INIT_MENU.INPUT:
                try {
                    manager1.inputData();
                } catch (InputException e) {
                    e.printStackTrace();
                }
                break;
            case INIT_MENU.SEARCH:
                manager2.searchData();
                break;
            case INIT_MENU.DELETE:
                manager3.deleteData();
                break;                
            case INIT_MENU.EXIT:
                System.out.println("프로그램을 종료합니다.");
                return;
            }
        }
    }
}
 

package _1020_B;
 
public class InputException extends Exception 
{
    public InputException(int num)
    {
        super(num + "은 잘못된 입력입니다.");
    }
}