invalid stream header问题的解决

今天调试一个http接口，调用端代码如下
URL url = new URL("http://www.AAA.com");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
ObjectOutputStream out = new ObjectOutputStream(connection.getOutputStream());

        Map map = new HashMap();
        map.put("type", "ttt");
        out.writeObject(map);
        out.flush();
        out.close();
服务端代码如下：
InputStream is = ####;
            ObjectInputStream ois = new ObjectInputStream(is);//异常产生出
            Map map = (Map) ois.readObject();
            ois.close();
            is.close();
服务端在异常产生出报invalid stream header异常，跟踪代码发现是ObjectInputStream(InputStream in)方法中会检查stream的头信息readStreamHeader()，头信息异常导致invalid stream header产生，检查调用端的代码发现没有设置Content-Type，因为是用序列号的二进制流，类型为application/xml，加上一句connection.setRequestProperty("Content-Type", "application/xml")，问题解决