[자바] 멀티미디어자바프로젝트II ch.08 연습문제

파일 입출력 문제

 

 

프로그램을 실행하면, 파일을 읽고(없으면 예외처리) 지정한 형식에 맞게 문자열을 나누어 Vector<Person>에 자동으로 집어넣어서 프로그램이 원활하게 작동하도록 하였다.

 

package _1103A;
 
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
import java.util.Vector;
 
public class Main {
 
    public static Scanner Keyboard = new Scanner(System.in);
    public static Vector<Person> PersonData = new Vector<Person>();
    private static String FileName = "PersonData.txt";
 
    public static void main(String[] args) {
 
        LoadTextData();
 
        while (true) {
            DisplayMenu();
 
            switch (Keyboard.nextInt()) {
            case 1: {
                InputData();
                System.out.println();
                break;
            }
            case 2: {
                DisplayAllData();
                System.out.println();
                break;
            }
            case 3: {
                System.out.println("프로그램을 종료합니다.");
                return;
            }
            case 4: {
                RemoveFile();
                System.out.println();
                break;
            }
            }
        }
    }
 
    public static void RemoveFile() {
        File file = new File(FileName);
        if (file.exists()) {
            if (file.delete()) {
                System.out.println("파일삭제 성공");
                PersonData.clear();
            } else {
                System.out.println("파일삭제 실패");
            }
        } else {
            System.out.println("파일이 존재하지 않습니다.");
        }
    }
 
    public static void LoadTextData() {
        BufferedReader in = null;
        StringBuilder str = new StringBuilder();
        try {
            in = new BufferedReader(new FileReader(FileName));
            String line;
            while (true) {
                line = in.readLine();
                if (line == null)
                    break;
                str.append(line);
            }
            InputDataFromFileStream(str);
        } catch (FileNotFoundException e) {
            System.out.println("파일이 없습니다!");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
 
    public static void InputDataFromFileStream(StringBuilder fileStream) {
 
        StringBuilder strName = new StringBuilder();
        StringBuilder strAge = new StringBuilder();
 
        for (int i = 0; i < fileStream.length(); ++i) {
            if (fileStream.charAt(i) == '{') {
                ++i;
 
                strName.setLength(0);
                strAge.setLength(0);
 
                for (int j = i; j < fileStream.length(); ++j, ++i) {
                    if (fileStream.charAt(i) == ',') {
                        ++j;
                        ++i;
                        break;
                    }
                    strName.append(fileStream.charAt(i));
                }
                for (int j = i; j < fileStream.length(); ++j, ++i) {
                    if (fileStream.charAt(i) == '}') {
                        break;
                    }
                    strAge.append(fileStream.charAt(i));
                }
 
                PersonData.add(new Person(strName.toString(), Integer.parseInt(strAge.toString())));
            }
        }
    }
 
    public static void InputData() {
 
        Keyboard.nextLine();
 
        BufferedWriter out = null;
 
        String nameInput;
        int ageInput;
 
        try {
            out = new BufferedWriter(new FileWriter(FileName, true));
 
            System.out.print("이름: ");
            nameInput = Keyboard.nextLine();
 
            System.out.print("나이: ");
            ageInput = Keyboard.nextInt();
 
            PersonData.add(new Person(nameInput, ageInput));
            out.write('{' + nameInput + ',' + ageInput + "}, ");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
 
    }
 
    public static void DisplayAllData() {
 
        if (PersonData.size() == 0) {
            System.out.println("데이터가 없습니다.");
            return;
        }
 
        for (Person person : PersonData) {
            person.DisplayInfo();
        }
    }
 
    public static void DisplayMenu() {
        System.out.println("== 메뉴 ==");
        System.out.println("1. 입력");
        System.out.println("2. 출력");
        System.out.println("3. 종료");
        System.out.println("4. 파일 제거");
        System.out.print("무엇을 하시겠습니까? ");
    }
}

 

package _1103A;
 
public class Person {
    private String mName;
    private int mAge;
    
    public Person(String name, int age)
    {
        this.mName = name;
        this.mAge = age;
    }
    
    public void DisplayInfo()
    {
        System.out.println("이름: " + this.mName);
        System.out.println("나이: " + this.mAge);
    }
}