通过http协议发送image / png

Question

我目前正在编写Java Web Server。到目前为止，它可以发送htmt，css ...文件，但发送图像不起作用。经过一些研究，我发现你需要发送图像二进制数据。该http响应的代码：

response = "HTTP/1.1 200 \r\n";
        response += "Server: Java Web Server/1.0 \r\n";
        response += "Content-Type: image/png \r\n";
        response += "Connection: close \r\n";
        response += "Content-Length: " + f.length() + " \r\n";
        response += "\r\n";

        response += getBinaryCode(f);

getBinaryCode方法：

private static String getBinaryCode(File f) {
    BufferedImage image;
    try {
        image = ImageIO.read(f);
        ByteArrayOutputStream b = new ByteArrayOutputStream();
        ImageIO.write(image, "png", b);
        byte[] jpgByteArray = b.toByteArray();
        StringBuilder sb = new StringBuilder();
        for (byte by : jpgByteArray)
            sb.append(Integer.toBinaryString(by & 0xFF));

        return sb.toString();
    } catch (IOException e) {
        e.printStackTrace();
    }

    return "";
}

问题是图像没有显示在 浏览器。有任何想法吗？提前谢谢！