[Java 연습 문제] Text file 입출력

문제

텍스트 파일의 이름을 main 함수의 argument로 받아서 파일의 내용을 요약해서 출력.
터미널에서 java FileDetails Yesterday.txt 하면 txt파일을 넘겨주면서 실행한다.

 

Text file

/* Yesterday.txt */
Yesterday

Yesterday, All my trouble seemed so far away
Now it looks as though they're here to stay
Oh, I believe in yesterday
Suddenly, I'm not half the man I used to be
There's a shadow hanging over me
Oh, yesterday came suddenly

Why she had to go, I don't know she wouldn't say
I said something wrong, now I long for yesterday
Yesterday, Love was such an easy game to play
Now I need a place to hide away
Oh, I believe in yesterday

Why she had to go, I don't know she wouldn't say
I said something wrong, now I long for yesterday
Yesterday, Love was such an easy game to play
Now I need a place to hide away
Oh, I believe in yesterday

 

(1) Text file의 내용을 출력

/* Yestereday.txt 파일의 내용을 출력해서 보여줌 */

import java.io.FileInputStream;
import java.io.File;

public class test {
    public static void main(String[] args) {
        if (args.length != 1) {
            System.out.println("Usage: java FileDetails FileName");
            return;
        }
        String fileName = args[0];
        File file = new File(fileName);
        try (FileInputStream stream = new FileInputStream(file)) {
            char[] contents = new char[(int)file.length()];
            for (int i = 0; i < contents.length; i++) {
                contents[i] = (char)stream.read();
            }
            for (char c: contents) {
                if (c == '\n') {
                    System.out.print("\n");
                }
                else {
                System.out.print(c);
                }
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 

(1) 실행 결과

Yesterday

Yesterday, All my trouble seemed so far away
Now it looks as though they're here to stay
Oh, I believe in yesterday
Suddenly, I'm not half the man I used to be
There's a shadow hanging over me
Oh, yesterday came suddenly

Why she had to go, I don't know she wouldn't say
I said something wrong, now I long for yesterday
Yesterday, Love was such an easy game to play
Now I need a place to hide away
Oh, I believe in yesterday

Why she had to go, I don't know she wouldn't say
I said something wrong, now I long for yesterday
Yesterday, Love was such an easy game to play
Now I need a place to hide away
Oh, I believe in yesterday

 

(2) Yesterday.txt의 상세 정보 출력

/* 입력받은 txt 파일의 상세 정보를 출력 */
import java.io.*;

public class FileDetails {

    public static void summerize(char[] contents) {

        // vowel: 모음, Consonant: 자음
        int vowel=0, consonats=0, lines=0;

        for (char c : contents) {
            if (Character.isLetter(c)) {    // Chracter.isLetter -> 글자면 true를 return한다. 아니면 false
                if ("AEIOUaeiou".indexOf(c) != -1) { // indexOf(char)는 argument로 char을 넣으면 해당 char에 대한 index를 return한다. 그래서 "0 ~ 배열의 크기" 까지 값이 나올 수 있다.
                    vowel++;
                }
                else { // 위의 if가 아니라는 말은 자음이니까
                    consonats++;
                }
            }
            else if (c == '\n') { // '\n'을 만나면 -> 줄바꿈하라는 뜻이니까 1줄이 끝났다는것. 그래서 lines++함.
                lines++;
            }
        }
        System.out.println("Total character count:" + contents.length);
        System.out.println("Vowel count: " + vowel); // 모음 수
        System.out.println("Consonats count: " + consonats); // 자음 수
        System.out.println("Line count: " + lines); // 줄 수
    }

    public static void main(String[] args) {

        if (args.length != 1) {
            System.out.println("Usage: java FileDetails <file name>");
            return;
        }

        String fileName = args[0]; // fileName에 Yesterday.txt가 저장된다.

        // read the file that passed from parameter of main method.
        File file = new File(fileName); // java.io.File 클래스를 사용한다, File 클래스의 객체 file을 생성하고 argument로 fileName을 넘겨준다. 이게 경로가 된다. Yesterday.txt 가 경로가됨

        // try에 이렇게 () 있으면 try with resource 다.
        // try with resource : try절을 나가면 filestream을 무조건 닫아준다. 즉, 오류가 발생하면 무조건 닫아준다는것.
        try (FileInputStream stream = new FileInputStream(file)) {
            char[] contents = new char[(int)file.length()];
            for (int i=0; i<contents.length; i++) {
                contents[i] = (char)stream.read(); // .read() 하면 int를 반환하기 때문에 형변환 해줘야함.
            }
            // for(char c : contents) {
            //     System.out.print(c);
            summerize(contents);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 

 

실행 결과

/* 터미널에 입력 */
> javac FileDetails.java
> java FileDetails Yesterday.java

Total character count:658
Vowel count: 192
Consonats count: 299
Line count: 19

 

 

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2024.08.25 - [Java] - [Java] 06. 배열

[Java] 06. 배열

 

 

출처: https://github.com/gikpreet/class-programming_with_java/tree/master

GitHub - gikpreet/class-programming_with_java