Java - Converti immagine in Base64

Question

Sto riscontrando un problema durante la conversione di un'immagine gif in una stringa 64 di base.

Quando lo converto, il codice mi aggiunge 100.000 AAAAAA mentre l'immagine è veramente piccola!

Ecco il mio codice:

import java.io.BufferedWriter; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileWriter; 
import java.util.ArrayList; 

public class Main 
{ 

    public static void main(String[] args) 
    { 
     try 
     { 
      FileWriter fstream = new FileWriter("./out.txt"); 
      BufferedWriter out = new BufferedWriter(fstream); 

      File folder = new File("./flags/"); 
      File[] listOfFiles = folder.listFiles(); 

      for (int i = 0; i < listOfFiles.length; i++) 
      { 
       if (listOfFiles[i].isFile()) 
       { 
        Main.readFile(out, listOfFiles[i]); 
       } 
      } 

      out.close(); 
      System.out.println("Done"); 
     } 
     catch (Exception e) {} 
    } 

    public static void readFile(BufferedWriter out, File file) 
    { 
     try 
     { 
      byte[] byteArray = new byte[102400]; 
      FileInputStream fis = new FileInputStream(file); 
      String base64String; 
      int bytesRead = 0; 
      while ((bytesRead = fis.read(byteArray)) != -1) 
      { 
       new String(byteArray, 0, bytesRead); 
       base64String = Base64.encode(byteArray); 
       out.write("public static ImageIcon getFlag" + file.getName() + "()"); 
       out.newLine(); 
       out.write("{"); 
       out.newLine(); 
       ArrayList<String> array = Main.cut(base64String); 
       out.write("return Utils.toImage(\"" + array.get(0) + "\""); 
       for (int i=1; i<array.size()-1; i++) 
       { 
        out.write("<tab>+\"" + array.get(i) + "\""); 
       } 
       out.write("<tab>\"" + array.get(array.size() - 1) + "\");"); 
       out.newLine(); 
       out.write("}"); 
       out.newLine(); 
       out.newLine(); 
      } 
     } 
     catch (Exception e) 
     { 
      e.printStackTrace(); 
     } 
    } 

    public static ArrayList<String> cut(String in) 
    { 
     ArrayList<String> array = new ArrayList<String>(); 
     while (in.length() > 76) 
     { 
      array.add(in.substring(0, 77)); 
      in = in.substring(77); 
     } 
     return array; 
    } 
} 

Basicaly, si scrive in un file di testo out.txt un mazzo di metodi Java con il codice di base 64 all'interno.

Ecco una (piccola) parte dell'output:

return Utils.toImage("R0lGODlhEAALANUAANPTAPZva/n5AfLySPz8iYqY3O01NgoksbGZa+kYGOskJKi05vb2XZ+r4+05O"<tab>+"Pv7eO3tKPv7bZak4dSvebC76tC2iPNISPX1UMkAAMm6U/NWTeYAAF5y1LqlevNaWpSh3e7uQ+1CQt"<tab>+"gAAKOv5Vds1C1IvpGf37a/7OnTYZ6q6NGkamd71/LyPusvLvFiTEFbx9rPb/HuaczATd7eAPAAAH2"<tab>+"N2vE+PMqiYuXQUsKufJqn4jlRxUlhy+CpelFnz/PxbyH5BAAAAAAALAAAAAAQAAsAAAaQwBVnSBIY"<tab>+"jzTaZsk5OSmEKOHxCAQ8nk1zMUo9Ir8Y42Kx2Dyi5qihi1QqkxzZZtCISBS2JNILoFQDdC0WIj4UO"<tab>+"hImDBMoLjcsBi0KISI8C4kFMB0uOAgykgkOGC8LJgUFFx0IqxAKCQkGGDsjpzUDLBkZEBCvCS0YJW"<tab>+"wfBQxjAyAgDpG/OwfOBzPRANMY1dVBADsAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab>+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"<tab> 

Grazie.

Edit: sto usando il codice base64 da questa domanda: https://stackoverflow.com/a/4265472/1295422

Answer 1

byte[] byteArray = new byte[102400]; 
base64String = Base64.encode(byteArray); 

Tale codice codificherà 102400 byte, indipendentemente dalla quantità di dati effettivamente utilizzati nell'array.

while ((bytesRead = fis.read(byteArray)) != -1) 

È necessario utilizzare il valore di byteLeggi da qualche parte.

Inoltre, questo non può leggere l'intero file nell'array in un colpo solo (si legge tanto quanto nel buffer I/O), quindi il ciclo probabilmente non funzionerà, si potrebbe finire con un mezzo immagine nel tuo array.

userei Apache Commons IOUtils qui:

Base64.encode(FileUtils.readFileToByteArray(file)); 

Answer 2

per cominciare, questa riga di codice:

while ((bytesRead = fis.read(byteArray)) != -1) 

equivale a

while ((bytesRead = fis.read(byteArray, 0, byteArray.length)) != -1) 

Quindi è scrivendo in byteArray dall'offset 0, piuttosto che da dove hai scritto prima.

avete bisogno di qualcosa di simile:

int offset = 0; 
int bytesRead = 0; 

while ((bytesRead = fis.read(byteArray, offset, byteArray.length - offset) != -1) { 
    offset += bytesRead; 
} 

Dopo aver letto i dati (byte) in poi, è possibile convertirlo in Base64.

Ci sono però problemi più grandi: si sta utilizzando una matrice di dimensioni fisse, quindi i file troppo grandi non verranno convertiti correttamente e il codice è anche più complesso.

avrei fosso di byte e andare con qualcosa di simile:

ByteArrayOutputStream buffer = new ByteArrayOutputStream(); 
// commons-io IOUtils 
IOUtils.copy(fis, buffer); 
byte [] data = buffer.toByteArray(); 
Base64.encode(data); 

O condensare ulteriormente come Thilo ha con fileutils.

Answer 3

La linea

base64String = Base64.encode(byteArray); 

converte la gamma completa (102400 bytes) per Base64, non solo il numero di byte che avete letto. Hai bisogno di passarlo il numero di byte.

Answer 4

new String(byteArray, 0, bytesRead); non modifica la matrice. È necessario utilizzare System.arrayCopy per tagliare l'array alla dimensione effettiva dei dati. Altrimenti si stanno elaborando tutti i 102400 byte la maggior parte dei quali sono zeri.

Answer 5

tardo GraveDig ... Basta limitare l'array di byte per la dimensione del file.

FileInputStream fis = new FileInputStream(file); 
byte[] byteArray= new byte[(int) file.length()]; 

Answer 6

È possibile utilizzare il file oggetto per ottenere la lunghezza del file per inizializzare l'array:

int length = Long.valueOf(file.length()).intValue(); 
byte[] byteArray = new byte[length]; 

Answer 7

È possibile creare una matrice di grandi dimensioni e poi copiarlo su un nuovo array utilizzando System.arrayCopy

 int contentLength = 100000000; 
     byte[] byteArray = new byte[contentLength]; 

     BufferedInputStream inputStream = new BufferedInputStream(connection.getInputStream()); 
     while ((bytesRead = inputStream.read()) != -1) 
     { 
      byteArray[count++] = (byte)bytesRead; 
     } 

     byte[] destArray = new byte[count]; 
     System.arraycopy(byteArray, 0, destArray , 0, count); 

destArray conterrà le informazioni che si desidera

Answer 8

mi rendo conto che questo è una vecchia domanda ma forse qualcuno troverà utile il mio esempio di codice. Questo codice codifica un file in Base64 quindi lo decodifica e lo salva in una nuova posizione.

import java.io.IOException; 
import java.nio.file.Files; 
import java.nio.file.Path; 
import java.nio.file.Paths; 
import java.util.Arrays; 

import org.apache.commons.codec.binary.Base64; 

public class Base64Example { 

    public static void main(String[] args) { 

     Base64Example tempObject = new Base64Example(); 

     // convert file to regular byte array 
     byte[] codedFile = tempObject.convertFileToByteArray("your_input_file_path"); 

     // encoded file in Base64 
     byte[] encodedFile = Base64.encodeBase64(codedFile); 

     // print out the byte array 
     System.out.println(Arrays.toString(encodedFile)); 

     // print the encoded String 
     System.out.println(encodedFile); 

     // decode file back to regular byte array 
     byte[] decodedByteArray = Base64.decodeBase64(encodedFile); 

     // save decoded byte array to a file 
     boolean success = tempObject.saveFileFromByteArray("your_output_file_path", decodedByteArray); 

     // print out success 
     System.out.println("success : " + success); 
    } 

    public byte[] convertFileToByteArray(String filePath) { 

     Path path = Paths.get(filePath); 

     byte[] codedFile = null; 

     try { 
      codedFile = Files.readAllBytes(path); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 

     return codedFile; 
    } 

    public boolean saveFileFromByteArray(String filePath, byte[] decodedByteArray) { 

     boolean success = false; 

     Path path = Paths.get(filePath); 

     try { 
      Files.write(path, decodedByteArray); 
      success = true; 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

     return success; 
    } 
}