java - 如何在java中将图像转换为字节数组？(不使用bufferedimage)

Question

大家好，请解释一下如何在 java 中将图像数据转换为字节数组，我正在尝试这样做。我不需要在这里使用缓冲图像。

File file = new File("D:/img.jpg");
        FileInputStream imageInFile = new FileInputStream(file);
        byte imageData[] = new byte[(int) file.length()];
        imageInFile.read(imageData);

Answer 1

您也可以使用 FileInputStream 转换图像数据。

File file = new File("D:\\img.jpg");

FileInputStream fis = new FileInputStream(file);
 //Now try to create FileInputStream which obtains input bytes from a file. 
 //FileInputStream is meant for reading streams of raw bytes,in this case its image data. 
 //For reading streams of characters, consider using FileReader.

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] buf = new byte[1024];
        try {
            for (int readNum; (readNum = fis.read(buf)) != -1;) {
                //Now Write to this byte array output stream
                bos.write(buf, 0, readNum); 
                System.out.println("read " + readNum + " bytes,");
            }
        } catch (IOException ex) {
            Logger.getLogger(ConvertImage.class.getName()).log(Level.SEVERE, null, ex);
        }

        byte[] bytes = bos.toByteArray();