将Json值从Android发布到服务器，并使用SQL将数据返回到Android

我正在尝试将json数据从android发布到php并使用值运行sql查询，但我做不到，我的想法是从android设备获取值，将该值发布到php并使用该值运行sql查询，然后将sql中的数据返回给android。

android代码：

        try {
        JSONObject toSend = new JSONObject();
        toSend.put("msg", "55555");

        JSONTransmitter transmitter = new JSONTransmitter();
        transmitter.execute(new JSONObject[] {toSend});

    } catch (JSONException e) {
        e.printStackTrace();
    }

public class JSONTransmitter extends AsyncTask<JSONObject, JSONObject, JSONObject> {

            String url = "http://site/file.php";

            @Override
            protected JSONObject doInBackground(JSONObject... data) {
            JSONObject json = data[0];
            HttpClient client = new DefaultHttpClient();
            HttpConnectionParams.setConnectionTimeout(client.getParams(), 100000);

            JSONObject jsonResponse = null;
            HttpPost post = new HttpPost(url);
            try {
                StringEntity se = new StringEntity("json="+json.toString());
                post.addHeader("content-type", "application/x-www-form-urlencoded");
                post.setEntity(se);

                HttpResponse response;
                response = client.execute(post);
                String resFromServer = org.apache.http.util.EntityUtils.toString(response.getEntity());

                jsonResponse=new JSONObject(resFromServer);
                Log.i("Response from server", jsonResponse.getString("msg"));
            } catch (Exception e) { e.printStackTrace();}

            return jsonResponse;
            }
        }

php代码：

    <?php

//include 'config.php';

if( isset($_POST["json"]) ) {
     $value = $_POST["json"]; 

    $sql = "SELECT * from table WHERE Code = '".$value."'";
    $result = mysql_query($sql);

    $json = array(); 
    if(mysql_num_rows($result)){
        while($row=mysql_fetch_assoc($result)){
        $json['myarray'][]=$row;
        }

    }else{
    }
}

mysql_close($con);
echo json_encode($json);
?> 

返回的$ value是

'{"msg":"55555"}'

我希望它返回：

55555