Java HttpClient改变内容类型？

Question

我正在为我的Android手机构建一个小应用程序,使用非常基本的REST界面将文本消息转发到Web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webservice.设置完全开箱即用.基本上有一个端点接收包含消息信息(发送者,正文,日期)的JSON对象的POST.我使用cURL使用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应用程序.它是一个简单的BroadcastReceiver子类,包含一个私有的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();
    }


}

正如您所看到的,我刚刚开始熟悉Java和Android SDK,所以请耐心等待.这个设置实际上在我构建的另一个应用程序中运行良好,可以将JSON字符串发送到Neo4J Web服务.

问题是,当我通过Android将消息发布到我的webservice时,在某些时候内容类型从'application/json'变为'application/json,application/json'.header循环中的日志条目仍然为每个标头输出正确的值,但是,webservice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

改变这个:

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

仅限于此:

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