txt文件到java中的二維數組

Question

我正在努力滿足這個社區的要求。 我已經為這個問題動了十個小時左右。 我很少尋求幫助，因此請諒解我是否不完全合規。

我被分配去做一個Java代碼，它將讀取一個ASCII圖像的文本文件。 文本文件的第一行是圖像的尺寸，忽略第一行。 我在填充字符數組時有些惡魔。 當我使用偽文本時，程序會輸出正確大小的數組，但無法獲取它來存儲文件中的實際字符。 我絕對可以確定我遇到了一些1D1OT錯誤，其中可能有很多垃圾代碼。 我試圖清理它，但是我主要關注寫文件的失敗。

另外：是的，這絕對是一項家庭作業。 全面披露。 否則，我不會為該任務使用數組。 但是，分配任務的時間不得超過一周。 我真的不想成為想要您為他們工作的人之一。

import java.util.*;
import java.io.*;


public class Shell{

    private static String fileName = null;
    private static int imageHeight =0;
    private static int imageWidth=0;
    private static char[][] buffer = null;
    private static Scanner input;
    private static Scanner in;
    private static Scanner in2;
    private static Scanner inFile;

    /*
    FUNCTION NAME: Main ;
    INPUT: none.
    OUTPUT: a message to the user of this program, all of the
    prompts and a final display according to user specifications.
    PRECONDITIONS:  None.
    POSTCONDITIONS: Variables and calls made according to users input
                    output set to start on a new line.
    CALLERS: None.
    CALLEES: askPermission, getParameters(), getImage(), and doTileJob().

     */

    public static void main(String args[]) throws FileNotFoundException
    {

    //in = new Scanner(System.in);
    //System.out.println("What file name would you like to print?");
    //String fileName = in.nextLine();
    //input = new Scanner(new File(fileName));

    boolean a = askPermission();
        if (a == true) { 
            while (a == true) {
                System.out.println("What is the name of the file you want printed?");
                in = new Scanner(System.in);
                fileName = in.nextLine();
                new Scanner(new File(fileName));
                System.out.println(fileName);
                getParameters();
                buffer = new char[imageHeight][imageWidth];
                getImage();
                printImage();
                a = askPermission();}
        }
        //else if (a == false) {
            System.out.println("Goodbye!");

        //}

    }



    /*
    FUNCTION NAME: askPermission ;
    INPUT: none.
    OUTPUT: a message to the user of this program.
    PRECONDITIONS:  output set to start on a new line.
    POSTCONDITIONS: variable response has user's answer stored in it.
    CALLERS: the main program
    CALLES: None.

     */

    public static boolean askPermission()
    {
        System.out.println("Would you like to print an image in a file?");
        System.out.println("If yes, type 'y'. If no, type 'n'");

        in2 = new Scanner(System.in);
        String Ans = in2.nextLine();
        if (Ans.equals("y")){
        return true;}

        else {
        return false;
        }
    }


    /*
   FUNCTION NAME getParameters ;
   INPUT: the file name, number of tiles across and down.
   OUTPUT: message "Getting Image".
   PRECONDITIONS: the variable response has 'y' in it.
   POSTCONDITIONS: variables set with the values entered by user.
   CALLERS: the main program
   CALLEES: none
     */

    static void getParameters() throws FileNotFoundException
    {   
        inFile = new Scanner(new File(fileName));
        imageHeight = (inFile.nextInt());  
        imageWidth = (inFile.nextInt());

    }

    /*
    FUNCTION NAME: getImage ;
    INPUT:the file name and the height and width of the pattern to be made.
    OUTPUT: the message "Getting Image".
    PRECONDITIONS: array for image declared, the variables fileName, 
                   imageHeight and imageWidth set with proper values.  
    POSTCONDITIONS: the image is stored in the array.
    CALLERS: the main program
    CALLEES: none
     */
    public  static void getImage() throws FileNotFoundException
{   
    String string = "";
    input = new Scanner(new File(fileName));

        {
        for (int n = 0; n<(imageHeight);) 
        {  

            string = input.nextLine();
            char[] charArray = new char[n];
            string = string + input.nextLine();
            charArray = string.toCharArray();       
            System.out.println(charArray[n]);
            char q = charArray[n];
            buffer[n][0] = (q);


            for(int p = 1; p<(imageWidth); p++) 
            {

                char[] charArrayW = string.toCharArray();       
                char a = charArrayW[p];
                buffer[n][p] = (a);

            }
           n=n+1;
        }
    }
}








    /*
    FUNCTION NAME: printImage
    INPUT:the buffer with the image and the height and width of the
          pattern to be made
    OUTPUT: the patterns structured according to users input.
    PRECONDITIONS: All of the variables are set and pattern is stored in 'buffer'.
    POSTCONDITIONS: Output displayed according to users input.
    CALLERS: the main program
    CALLEES: none
     */
    //  This function uses for loops to display the images. The inner most for loop prints one line of the picture.


    public  static void printImage()
    {
        for ( int i=0; i<imageHeight; i++) {
            System.out.print (buffer[i][0]);
            //System.out.println();
            for(int j=0; j<imageWidth; j++) 
                System.out.print (buffer[i][j]);
                System.out.println();}
    }
    }

現在看來，我是如此接近。 我得到的問題是，在getImage（）中，我在第126行接收到“找不到行”異常。它只打印很少量的文件，在第一個垂直行僅打印幾個字符。

Answer 1

您的getImage方法中有幾個問題。 首先，您應該從包含寬度/高度的文件中跳過第一行。 其次，您正在讀取該行（每個循環迭代調用兩次input.nextLine() ），因此實際上需要2*imageHeight行。 難怪您無法正確閱讀它們。 接下來，出於某種原因將string與上一個字符串（ string = string + input.nextList() ）連接起來。 完全沒有必要。 接下來，我看到從char q = charArray[n]的行中提取第n-th字符並打印出來毫無意義。 n變量是行號，而charArray索引對應於列！ 同樣，無需在每個嵌套循環迭代中調用toCharArray() 。 最后，您需要使用try-with-resources語句關閉文件。 這是固定代碼：

public static void getImage() throws FileNotFoundException {
    String string = "";
    try(Scanner input = new Scanner(new File(fileName)))
    {
        input.nextLine(); // skip width/height
        for (int n = 0; n < (imageHeight);) {

            string = input.nextLine();
            char[] charArray = string.toCharArray();

            for (int p = 0; p < (charArray.length); p++) {

                char a = charArray[p];
                buffer[n][p] = (a);

            }
            n = n + 1;
        }
    }
}