JAVA读取二进制文件以及画图教程

DataInputStream(InputStream in)
Creates a DataInputStream that uses the specified underlying InputStream.

DataInputStream dis = null;
dis = new DataInputStream(new FileInputStream ("./test.txt"));
byte []b = new byte [1024];
dis.read(b);

BufferedInputStream(InputStream in)
Creates a BufferedInputStream and saves its argument, the input stream in, for later use.
BufferedInputStream(InputStream in, int size)
Creates a BufferedInputStream with the specified buffer size, and saves its argument, the input stream in, for later use.

BUfferedInputStream bis = null;
bis = new BufferedInputStream(new fileInputStream("./test.txt"));
int len = bis.available();
byte []b = new byte[len];
bis.read(b, 0, len);

int x = (buff[0] & 0xff) | (buff[1] & 0xff) << 8;
int y = (buff[2] & 0xff) | (buff[3] & 0xff) << 8;

 // create a BufferedImage with the size of (width, height)
        BufferedImage bufferedImage = new BufferedImage(width, height,                 
        BufferedImage.TYPE_INT_RGB);
        // to draw strokes, we need a Graphics2D - correlated with BufferedImage
        Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
        // set the background to be WHITE
        graphics2D.setBackground(Color.WHITE);
        graphics2D.clearRect(0, 0, width, height);
        // set width and color for lines
        graphics2D.setPaint(Color.BLACK);
        graphics2D.setStroke(new BasicStroke(3));

int pos;
        boolean bDrawing = false;
        int xPrev=-1, yPrev=-1;
        for( pos = 4; pos + 7 <= nLength ; pos += 7)
        {
            byte status = buffer[pos];
            int x = ((buffer[pos+1]&0xff) | ((buffer[pos+2]&0xff) << 8)) / 10;
            int y = ((buffer[pos+3]&0xff) | ((buffer[pos+4]&0xff) << 8)) / 10;
            if( bDrawing ) {
                if(status == 0x11) {
                    graphics2D.drawLine(xPrev, yPrev, x, y);
                    xPrev = x;
                    yPrev = y;
                }
                else {
                    bDrawing = false;
                }
            }
            else {
                if(status == 0x11) {
                    bDrawing = true;
                    xPrev = x;
                    yPrev = y;
                }
                else {
                    // floating
                }
            }
        }