IO流----------------将文件转成byte[]数组工具类

	public static byte[] getFileToByte(File file) {
        byte[] by = new byte[(int) file.length()];
        InputStream is =null;
        try {
        	is = new FileInputStream(file);
            ByteArrayOutputStream bytestream = new ByteArrayOutputStream();
            byte[] bb = new byte[2048];
            int ch;
            ch = is.read(bb);
            while (ch != -1) {
                bytestream.write(bb, 0, ch);
                ch = is.read(bb);
            }
            by = bytestream.toByteArray();
        } catch (Exception ex) {
            ex.printStackTrace();
        }finally {
        	try {
				is.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
        return by;
    }