File 转byte[]

 /**
     * 文件File转化为字节数组byte[]
     */
    public static byte[] getBytesFromFile(File f){    	
        if (f == null) {
            return null;
        }
        
        try {
            FileInputStream stream = new FileInputStream(f);
            ByteArrayOutputStream out = new ByteArrayOutputStream(1000);
            byte[] b = new byte[1000];
            int n;
            while ((n = stream.read(b)) != -1){
                out.write(b, 0, n);
            }
            stream.close();
            out.close();
            return out.toByteArray();
        } catch (IOException e){
        	e.printStackTrace();
        }
        return null;
    }