Java模拟POST请求发送二进制数据

public static void main(String[] args) {
    String result = "";
    try {
        String url = "http://localhost:8080/Demo/SiteApi";
        URL realUrl = new URL(url);
        // 打开和URL之间的连接
        URLConnection conn = realUrl.openConnection();
        // 设置通用的请求属性
        conn.setRequestProperty("accept", "*/*");
        conn.setRequestProperty("connection", "Keep-Alive");
        conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        conn.setRequestProperty("Content-Type", "application/octet-stream");
        // 发送POST请求必须设置如下两行
        conn.setDoOutput(true);
        conn.setDoInput(true);        
        
        // 发送请求参数
        DataOutputStream dos=new DataOutputStream(conn.getOutputStream());
        String content="I love china";
        dos.write(content.getBytes());        
        
        // flush输出流的缓冲
        dos.flush();
        // 定义BufferedReader输入流来读取URL的响应
        BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
        System.out.println(result);//打印输出结果
    } catch (Exception e) {
        System.out.println("异常," + e.getMessage());
        e.printStackTrace();
    }
}