[英]Convert Hex value to ASCII character from array and how to eliminate null value?
我在中間,試圖將我從我的方法中檢索到的十六進制值(compareHexaRGB)轉換為ASCII字符,我想知道將產生什么輸出。 我不知道我做錯了還是錯過了某個地方的代碼。
用於將十六進制值轉換為ASCII的extractMessage()方法的代碼:
public class extractMessage
{
private static String[][] char1;
private static String[][] char2;
private static String[][] in;
private static String[][] combine;
public static void extractMessage(String[][] inn, String[][] comb)
{
in = inn;
combine = comb;
}
public static void printString2DArray(String[][] in)
{
for (int i = 0; i < in.length; i++)
{
for(int j = 0; j < in[i].length; j++)
{
System.out.println(in[i][j] + " ");
}
System.out.println();
}
}
public static void charExtract()
{
compareHexaRGB hexRGB = new compareHexaRGB();
char1 = hexRGB.getCheck_hex2();
char2 = hexRGB.getCheck_hex4();
combine = new String[char1.length][char1[0].length];
for(int i = 0; i < char1.length; i++)
{
for(int j = 0; j < char1[i].length; j++)
{
//concatenate string
combine[i][j] = char1[i][j] + char2[i][j];
}
}
System.out.println("Char 1 + Char 2: ");
printString2DArray(combine);
}
public static String convertHexToString()
{
extractMessage em = new extractMessage();
StringBuilder sb = new StringBuilder();
StringBuilder temp = new StringBuilder();
String out = em.charExtract(); //error stated incompatible types: void cannot be converted to String
int decimal;
for(int i = 0; i < out.length(); i += 2)
{
String output = out.substring(i, (i + 2));
decimal = Integer.parseInt(output, 16);
sb.append((char)decimal);
temp.append(decimal);
}
System.out.println("Output: " + temp.toString());
return sb.toString();
}
}
其次,我仍然無法從檢索到的值中消除NULL值。 有人說我需要添加一個位置來容納字符,在這種情況下為NULL值。 我已經做到了,但是當我嘗試運行代碼時,我們再次嘗試執行nullpointerexception。 我還是Java的新手,也缺乏處理Java數組和高級Java的經驗,但是我很想學習。 Java是一種非常有趣的語言,我希望有一天我能精通這種語言。
compareHexaRGB()的代碼:
public class compareHexaRGB
{
private static int w;
private static int h;
private static BufferedImage img;
private static BufferedImage img2;
private static String[][] check_hex2;
private static String[][] check_hex4;
private static String[][] not_stega2;
private static String[][] not_stega4;
public static void compareHexaRGB(BufferedImage image, BufferedImage image2, int width, int height) throws IOException
{
w = width;
h = height;
img = image;
img2 = image2;
}
public void check() throws IOException
{
getPixelRGB1 pixel = new getPixelRGB1();
getPixelData1 newPD = new getPixelData1();
int[] rgb;
int count = 0;
int[][] pixelData = new int[w * h][3];
check_hex2 = new String[w][h];
check_hex4 = new String[w][h];
for(int i = 0; i < w; i++)
{
for(int j = 0; j < h; j++)
{
rgb = newPD.getPixelData(img, i, j);
for(int k = 0; k < rgb.length; k++)
{
pixelData[count][k] = rgb[k];
}
if(pixel.display_imgHex2()[i][j].equals(pixel.display_img2Hex2()[i][j]))
{
System.out.println("\nPixel values at position 2 are the same." + "\n" + pixel.display_imgHex2()[i][j] + " " + pixel.display_img2Hex2()[i][j]);
not_stega2[i][j] = pixel.display_img2Hex2()[i][j]; // i've done the same as check_hex2 and check_hex4 method but why the error still occur?
}
if(pixel.display_imgHex4()[i][j].equals(pixel.display_img2Hex4()[i][j]))
{
System.out.println("\nPixel values at position 4 are the same." + "\n" + pixel.display_imgHex4()[i][j] + " " + pixel.display_img2Hex4()[i][j]);
not_stega4[i][j] = pixel.display_img2Hex4()[i][j];
}
if(!pixel.display_imgHex2()[i][j].equals(pixel.display_img2Hex2()[i][j]))
{
System.out.println("\nPixel values at position 2 are not the same." + "\n" + pixel.display_imgHex2()[i][j] + " " + pixel.display_img2Hex2()[i][j]);
check_hex2[i][j] = pixel.display_img2Hex2()[i][j];
System.out.println("\nOutput Hex 2: " + check_hex2[i][j]);
}
if(!pixel.display_imgHex4()[i][j].equals(pixel.display_img2Hex4()[i][j]))
{
System.out.println("\nPixel values at position 4 are not the same." + "\n" + pixel.display_imgHex4()[i][j] + " " + pixel.display_img2Hex4()[i][j]);
check_hex4[i][j] = pixel.display_img2Hex4()[i][j];
System.out.println("\nOutput Hex 4: " + check_hex4[i][j]);
}
if(!pixel.display_imgHex2()[i][j].equals(pixel.display_img2Hex2()[i][j]) || (!pixel.display_imgHex4()[i][j].equals(pixel.display_img2Hex4()[i][j])))
{
System.out.println("\nOne of the pixel values at position 2 and 4 are not the same." + "\n" + pixel.display_imgHex2()[i][j] + " " + pixel.display_img2Hex2()[i][j] + "\n" + pixel.display_imgHex4()[i][j] + " " + pixel.display_img2Hex4()[i][j]);
if(!pixel.display_imgHex2()[i][j].equals(pixel.display_img2Hex2()[i][j]) || (pixel.display_imgHex2()[i][j].equals(pixel.display_img2Hex2()[i][j])))
{
check_hex2[i][j] = pixel.display_img2Hex2()[i][j];
System.out.println("\nOutput Hex 2: " + check_hex2[i][j]);
}
if(!pixel.display_imgHex4()[i][j].equals(pixel.display_img2Hex4()[i][j]) || (pixel.display_imgHex4()[i][j].equals(pixel.display_img2Hex4()[i][j])))
{
check_hex4[i][j] = pixel.display_img2Hex4()[i][j];
System.out.println("\nOutput Hex 4: " + check_hex4[i][j]);
}
}
count++;
System.out.println("\nOutput Count: " + count);
}
}
}
public String[][] getCheck_hex2()
{
return check_hex2;
}
public String[][] getCheck_hex4()
{
return check_hex4;
}
public String[][] getCheck_notStega2()
{
return not_stega2;
}
public String[][] getCheck_notStega4()
{
return not_stega4;
}
}
希望能盡快消除這些問題。 感謝任何幫助!
public static void charExtract()
{ ...
}
和
String out = em.charExtract(); //error stated incompatible types
顯然不匹配。 此外,為什么要嘗試在實例 em
上調用靜態方法charExtract()
?
您在這些String[][]
數組中存儲什么?
char1 = hexRGB.getCheck_hex2();
char2 = hexRGB.getCheck_hex4();
不知道它們應包含的內容,我們無法幫助您將其內容轉換為任何內容。
目前,我假設您真的不想處理“十六進制”數字; 與對任何數字的String表示相比,在int
上執行計算要容易得多。
如我所見,您的代碼中存在2個缺陷:
1.如果charExtract()方法是靜態的,則需要以靜態方式訪問它:
String out = extractMessage.charExtract();
2.其次,當您將值從charExtract()存儲到String變量“ out”時,您需要從charExtract()方法返回一個字符串,將其聲明為
public static String charExtract()
{ ...
}
並從charExtract返回一些值,例如:
return combine[o][1];
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