Java HttpClient更改内容类型？

Question

我正在为我的Android手机构建一个小型应用程序，以使用非常基本的REST界面将短信转发到网络服务器。

我正在使用android 4.0.3 SDK。我使用Django和Django
restframework包在python中开发了Web服务。设置完全是开箱即用的。基本上有一个端点可以接收包含消息信息（发送者，正文，日期）的JSON对象的POST。我已经使用cURL通过以下命令测试了该服务：

curl -X POST -H 'Content-Type: application/json' --data '{"sender":"+xxxxxxxx", "body": "test", "send_date":"2011-03-20 16:32:02"}' http://[...]/messages.json

一切正常，我得到了预期的响应：

{"body": "test", "send_date": "2011-03-20T16:32:02", "id": 25, "sender": "+xxxxxxxxxx"}

现在，我设置了android应用。这是一个简单的BroadcastReceiver子类，包括一个私有的AsyncTask类：

private class httpPost extends AsyncTask<String, Void, JSONObject> {
    protected JSONObject doInBackground(String... args) {
        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpParams myParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(myParams, 10000);
        HttpConnectionParams.setSoTimeout(myParams, 10000);

        String url = args[0];
        String json=args[1];            
        JSONObject JSONResponse = null;
        InputStream contentStream = null;
        String resultString = "";

        try {
            HttpPost httppost = new HttpPost(url);
            httppost.setHeader("Content-Type", "application/json");
            httppost.setHeader("Accept", "application/json");

            StringEntity se = new StringEntity(json); 
            se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
            httppost.setEntity(se);

            for (int i=0;i<httppost.getAllHeaders().length;i++) {
                Log.v("set header", httppost.getAllHeaders()[i].getValue());
            }

            HttpResponse response = httpclient.execute(httppost);

            // Do some checks to make sure that the request was processed properly
            Header[] headers = response.getAllHeaders();
            HttpEntity entity = response.getEntity();
            contentStream = entity.getContent();

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //convert response to string
        try{
            BufferedReader reader = new BufferedReader(new InputStreamReader(contentStream,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            contentStream.close();
            resultString = sb.toString();
        }catch(Exception e){
            e.printStackTrace();
        }

        Log.v("log", resultString);
        return new JSONObject();
    }


}

如您所见，我刚刚开始熟悉Java和android SDK，所以请多多包涵。实际上，此设置在我构建的用于将JSON字符串发送到Neo4J
Web服务的另一个应用程序中可以正常工作。

问题是，当我通过Android将消息发布到我的Web服务时，有时内容类型从’application / json’更改为’application /
json，application / json’。标头循环中的日志条目仍然为每个标头输出正确的值，但是，Web服务返回以下错误消息：

{"error": "Unsupported media type in request 'application/json, application/json'."}

我很困惑，欢迎任何帮助。

Answer 1

更改此：

StringEntity se = new StringEntity(json); 
se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
httppost.setEntity(se);

仅此：

httppost.setEntity(new StringEntity(json.toString(), HTTP.UTF_8));