android - HttpPost - ClientProtocolException

Question

http post JSON データをサーバーに投稿すると、例外が発生しますClientProtocolException 。このコードの何が問題なのか教えてもらえますか?

ログキャット

06-11 10:30:56.062: W/System.err(435): org.apache.http.client.ClientProtocolException
06-11 10:30:56.122: W/System.err(435):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:557)
06-11 10:30:56.182: W/System.err(435):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:653)
06-11 10:30:56.212: W/System.err(435):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:627)
06-11 10:30:56.212: W/System.err(435):  at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:616)
06-11 10:30:56.212: W/System.err(435):  at com.vector.syncfunc.MainActivity.post(MainActivity.java:168)

コード：

  private String post(String url) {

    String response = null;
    try {

        boolean exception = false;
        StringBuilder builder = new StringBuilder();
        builder.append(getDeviceId());
        builder.append("|||");
        builder.append(getLastSyncDate());
        builder.append("|||");
        builder.append(getCurrentDateStr());
        String dateStr = builder.toString();

        DefaultHttpClient httpclient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);
                    //httpPost.setHeader("Host", url);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader(HTTP.CONTENT_TYPE, "application/json");

        JSONObject jsonObject = new JSONObject();

        String param = null;
        try {
            param = encrypt(dateStr);
        } catch (InvalidKeyException e1) {
            e1.printStackTrace();
            exception = true;
        } catch (NoSuchAlgorithmException e1) {
            e1.printStackTrace();
            exception = true;
        } catch (NoSuchPaddingException e1) {
            e1.printStackTrace();
            exception = true;
        } catch (IllegalBlockSizeException e1) {
            e1.printStackTrace();
            exception = true;
        } catch (BadPaddingException e1) {
            e1.printStackTrace();
            exception = true;
        }

        if (exception) {
            return null;
        }

        try {
            jsonObject.put("encstring", param);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        httpPost.setHeader("Content-Length", ""+param.getBytes().length);
        StringEntity entity = new StringEntity(jsonObject.toString(),
                HTTP.UTF_8);
        entity.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
        httpPost.setEntity(entity);
        ResponseHandler responseHandler = new BasicResponseHandler();
        HttpResponse httpResponse = httpclient.execute(httpPost,
                responseHandler);
        StatusLine line = httpResponse.getStatusLine();
        if (line.getStatusCode() == 200) {
            HttpEntity httpEntity = httpResponse.getEntity();
            InputStream inputStream = httpEntity.getContent();

            response = readString(inputStream);
        }

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