Method transfer

src/main/java/io/xjar/XKit.java:120–130

输入流传输到输出流 @param in 输入流 @param out 输出流 @return 传输长度 @throws IOException I/O 异常

(InputStream in, OutputStream out)

     * @throws IOException I/O 异常
     */
    public static long transfer(InputStream in, OutputStream out) throws IOException {
        long total = 0;
        byte[] buffer = new byte[4096];
        int length;
        while ((length = in.read(buffer)) != -1) {
            out.write(buffer, 0, length);
            total += length;
        }
        out.flush();
        return total;
    }

    /**
     * reader传输到writer