Here is the code I'm using inside my AsyncTask
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");
HttpResponse response = httpClient.execute(request);
HttpEntity responseEntity = response.getEntity();
char[] buffer = new char[(int)responseEntity.getContentLength()];
InputStream stream = responseEntity.getContent();
InputStreamReader reader = new InputStreamReader(stream);
reader.read(buffer);
stream.close();
result = new String(buffer);
return result;
This returns a string result and in my onPostExecute method I try to parse that input string:
JSONObject vehicle = new JSONObject(new String(result));
makeEdit.setText(vehicle.getString("make"));
plateEdit.setText(vehicle.getString("plate"));
modelEdit.setText(vehicle.getString("model"));
yearEdit.setText(vehicle.getString("year"));
As soon as it reaches makeEdit.setText it throws an error - no value for make. I'm still very new to android, so don't send death threats if there was some obvious error. The input text is the following JSON string:
{"GetJSONObjectResult":{"make":"Ford","model":"Focus","plate":"XXO123GP","year":2006}}
No value for x error message is pretty common when dealing with JSON. This usually resulted by overlooked code.
usually, when dong JSON, I try to see the human readable structure first. For that, I usually use JSONViewer.
In your case, the structure is something like this:
You see that make is within another object called GetJSONObjectResult. Therefore, to get it, you must first get the container object first:
JSONObject vehicle = ((JSONObject)new JSONObject(result)).getJSONObject("GetJSONObjectResult");
//a more easy to read
JSONObject container = new JSONObject(result);
JSONObject vehicle = container.getJSONObject("GetJSONObjectResult");
and finally use the object to get make:
makeEdit.setText(vehicle.getString("make"));
plateEdit.setText(vehicle.getString("plate"));
modelEdit.setText(vehicle.getString("model"));
yearEdit.setText(vehicle.getString("year"));
Your JSON Object contains itself a JSONObject. To acces to your data, you have to do like this:
vehicle.getJSONObject("GetJSONObjectResult").getString("make");
Related
I have a servlet that has the following purpose:
Receive data via the URL (that is, using get). Then returns a message, based on this input, back to the caller. I am new to this stuff, but have come to learn that using json (actually, Gson) is suitable for this.
My question now is, how do I retrieve this json message? What URL do I target? The relevant lines in the servlet are:
String json = new Gson().toJson(thelist);
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().println(json);
This is how I try to retrieve the json:
try{
DefaultHttpClient defaultClient = new DefaultHttpClient();
HttpGet httpGetRequest = new HttpGet("http://AnIPno:8181/sample/response?first=5&second=92866");
HttpResponse httpResponse = defaultClient.execute(httpGetRequest);
BufferedReader reader = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent(), "UTF-8"));
String json = reader.readLine();
JSONObject jsonObject = new JSONObject(json);
} catch(Exception e){
e.printStackTrace();
}
But apparently this does not work, as I have found jsonObject has a size of 0 (it should be an array with three elements).
Previously, I had a write() instead of println() in the servlet. I'm not sure if that matters in this case. But I'm assuming I've misunderstood something about how the json object is retrieved. Is it not enough to point it towards the URL of the servlet?
Reading an InputStream whether from a File on the file system or from an HTTP request is, in most cases, the same.
What you have is correct only if your servlet wrote a single line. If the Gson object toString() method returns multiple lines, you're going to have to read multiple lines from the InputStream. I like to use the Scanner class for reading from an InputStream.
try {
DefaultHttpClient defaultClient = new DefaultHttpClient();
HttpGet httpGetRequest = new HttpGet("http://localhost:8080/cc/jsonyeah");
HttpResponse httpResponse = defaultClient.execute(httpGetRequest);
Scanner scanner = new Scanner(httpResponse.getEntity().getContent(), "UTF-8");
while(scanner.hasNextLine()) { // scanner looks ahead for an end-of-line
json += scanner.nextLine() + "\n"; // read the full line, you can append a \n
}
// do your serialization
} catch(Exception e) {
e.printStackTrace();
}
So we've done the same thing we would've done if we were reading from a file. Now the json object contains the json you received from the servlet, as a String.
For the serialization, you have a few options.
A Gson object has an overloaded method fromJson() that can take a String or a Reader, among other things.
From where we are with the code above, you can do
MyClass instance = new Gson().fromJson(json, MyClass.class);
where MyClass is the type you are trying to create. You will have to use a TypeToken for generic classes (such as a list). TypeToken is an abstract class, so generate an anonymous class and call getType()
Type type = new com.google.gson.reflect.TypeToken<List<String>>(){}.getType();
List<MyClass> list = new Gson().fromJson(json, type);
Another option is to use the overloaded method that takes a Reader directly instead of reading line by line from the InputStream:
BufferedReader reader = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent(), "UTF-8"));
MyClass instance = new Gson().fromJson(reader , MyClass.class);
You'll get to skip a step.
Don't forget to close your streams.
I have this function to readJsonData from a a request to a JSON String. You can use this function to retrieve the JSON, then use GSON to parse it to the object that you like. It works for my application. Hope it works for you too.
protected String readJson(HttpResponse resp)
throws IOException {
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(
resp.getEntity().getContent()));
StringBuffer buffer = new StringBuffer();
int read;
char[] chars = new char[1024];
while ((read = reader.read(chars)) != -1)
buffer.append(chars, 0, read);
} finally {
if (reader != null)
reader.close();
}
return buffer.toString();
}
So based on your code. I guess this should work:
String jsonData = readJson(httpResponse);
YourObject obj = new Gson().fromJson(jsonData, YourObject.class);
Before trying this, make sure your servlet prints out the JSON data that you want. I suggest using these Chrome Extensions: Postman - REST Client and JSON Formatter, to test your data from servlet. It's pretty helpful.
It has been a while since I programmed for Android and I have lost all my previous work which had the code in it I am having problems with. I am developing an app for both Android and iPhone which connect to the same server to download data. All is well in the iPhone version but on Android when I hit the server with the post data containing the method name I would like to to run on the server it seems that the data is not added to the request.
Why is the POST not working in this request for Android but does for the iPhone version of the app?
Here is the code I am using:
public static void makeRequest() throws Exception {
Thread t = new Thread() {
public void run() {
Looper.prepare(); //For Preparing Message Pool for the child Thread
HttpClient client = new DefaultHttpClient();
HttpConnectionParams.setConnectionTimeout(client.getParams(), 10000);
HttpResponse response;
HttpEntity entity;
JSONObject json = new JSONObject();
try {
HttpPost post = new HttpPost("http://divisi.co.uk/rest/requesthandler.php");
json.put("method", "getEventListData");
StringEntity se = new StringEntity(json.toString());
se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
post.setEntity(se);
response = client.execute(post);
entity = response.getEntity();
String retSrc = EntityUtils.toString(entity);
JSONObject result = new JSONObject(retSrc); //Convert String to JSON Object
if(result.getString("SC") == "200"){
JSONArray data = result.getJSONArray("data");
}
else{
}
} catch(Exception e) {
e.printStackTrace();
}
Looper.loop(); //Loop in the message queue
}
};
t.start();
}
The response I get mack from the server is:
{"data":{"scalar":""},"SC":405,"timestamp":1363788265}
Meaning the method name was not found, i.e. not posted in my request to the server.
heres an example of how i do things like this:
HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost("http://divisi.co.uk/rest/requesthandler.php");
MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
reqEntity.addPart(new FormBodyPart("method", new StringBody("getEventListData")));
reqEntity.addPart(new FormBodyPart("NEED_A_KEY_HERE", new StringBody("" + json.toString())));
postRequest.setEntity(reqEntity);
HttpResponse response = httpClient.execute(postRequest);
JSONObject responseDict = new JSONObject(EntityUtils.toString(response.getEntity()));
allow this is your "http://divisi.co.uk/rest/requesthandler.php" page code, then in android you can use this... you don't allow post in your URL,
use fiddler on your sever side. see if the http message is correct. it seems your sever side problem, can you show us your sever side code which receive and parse json.
If the server can't read your request try to remove:
se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
It will use the mime type defaults HTTP.PLAIN_TEXT_TYPE i.e. "text/plain".
I don't see any other possibility, if your code is the one you posted and not a more complicated input JSON object.
Your code to set the POST body may be just fine. I think the problem may be with your web service. Try using something like Rested or curl to manually make the call to your server. I made exactly the same request you are making, including with and without the POST body, and I got the same response from your server:
{"data":{"scalar":""},"SC":405,"timestamp":1365704082}
Some things that may be tripping you up:
JSONObject result = new JSONObject(retSrc); //Convert String to JSON Object
if(result.getString("SC") == "200"){
JSONArray data = result.getJSONArray("data");
}
Here, you are comparing the string "405" to "200" using ==, when you should first do a null check and then use .equals("200") instead. Or, use result.getInt("SC") == 200 since this is an integer type in your response JSON.
Also, the "data" entity from your server response is not actually coming back as a JSON array. You should use getJSONObject("data") instead.
Additionally, it's always a good idea to externalize your strings.
Here's how the code should look:
public static final String JSON_KEY_SC = "SC";
public static final String JSON_KEY_DATA = "data";
...
JSONObject result = new JSONObject(retSrc); //Convert String to JSON Object
String sc = result.getString(JSON_KEY_SC);
if (sc != null && sc.equals("200")) {
JSONObject data = result.getJSONObject(JSON_KEY_DATA);
}
else {
...
}
I use HttpClient in android to send post request:
HttpClient client = new DefaultHttpClient();
HttpPost request = new HttpPost(hostNameCollection);
StringEntity se = new StringEntity(jsonObj.toString());
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");
request.setEntity(se);
HttpResponse response = client.execute(request);
Log.v("HttpLogClient.logJSONObject", "wyslano JSON");
and I'dont know how I can receive JSON object on my Java EE servlet.
you need to read the response body text, then parse as JSON,
String result = EntityUtils.toString(response.getEntity());
JSONObject jo = new JSONObject(result);
read the body of the http post ( server-side ) by getting the a stream object on the body and then reading it.
Once youve read it , convert the bytes to chars and that will be json which you can use to build a json object like a jsonNode using 'jackson' libs.
If you are using plain servlets the json stream is located in the body of the HttpServletRequest : request.getReader() or request.getInputStream();
To make things easier you could use a library handling databinding for you.
Have a look at Genson http://code.google.com/p/genson/.
YouClass object = new Genson().deserialize(request.getReader(), YourClass.class);
// or to a plain map
Map<String, Object> map = genson.deserialize(request.getReader(), Map.class);
I'm getting back names of (Foursquare) venues from a server call where the names of the venues returned can be in English or non-English.
Assume the venue name is in a JSON object as follows:
{...
"name":"venue name which can be in any language"
...}
I'm creating a JSONObject from this response and then pulling out the name of the venue as follows:
String name = jsonObject.getString("name");
Lastly, I'm setting the TextView's text to show the name of the venue as follows:
myTextView.setText(name);
I'm finding however for Arabic names that where the Arabic characters are joined in the original JSON object (as they should be), the characters that show in the app (i.e. in the TextView) are disjoint. (I'm not too familiar with other languages so can't really tell if they're showing incorrectly too.)
Is there something additional I should be doing to pull out non-English names correctly from the JSON object and setting it as the text of a TextView, or is it down to the phone to decide how the text will be displayed?
Edit: I've tried parsing the server response (as suggested by #bbedward) explicitly specifying the content encoding as UTF-8 as follows...
HttpEntity httpEntity = httpResponse.getEntity();
String responseMessage = EntityUtils.toString(myHttpEntity, "UTF-8");
JSONObject jsonObject = new JSONObject(responseMessage);
... but still no joy. (Arabic characters appear, as before, disjoint in words where they should be joint up.) Could it be a phone thing or is there something extra needing to be done myself to get the words/characters to show proper in non-English languages? Perhaps the server needs to explicitly specify a "Content-Type" header with value "UTF-8"?
I'm going to answer anyway, I'm guessing you aren't getting your json in UTF-8 as i had a similar problem, I believe json won't come any other way.
Complete Example
The only things to concern yourself with this is setting the encoding for the InputStreamReader and creating the JSONObject
private DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httppost = new HttpPost("http://myjsonurl.com/search?type=json");
// Depending on your web service
httppost.setHeader("Content-type", "application/json");
try
{
String result = null;
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
JSONObject myJObject = new JSONObject(sb.toString();
}
catch (Exception e)
{
}
finally
{
try{if(inputStream != null)inputStream.close();}catch(Exception none){}
}
add this line when you connect to mysql:
mysql_set_charset('utf8', $con);
ex:
$con = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
mysql_set_charset('utf8', $con);
mysql_select_db(DB_DATABASE);
Hi i am trying to parse the string and convert it in to JSONObject.But it is not converted and giving the error like
"07-28 11:36:47.674: WARN/System.err(6050): org.json.JSONException: Unterminated string at character 3136 of {"data":[{""...."(there is my data)
First i thought there is some special characters like ~,#,%,& and replace the characters with " " but there is no result and giving the same error.
And i modified the web services data by encoding with UTF-8 format. and i used the code to get decode the UTF-8 formatted data in my application.here is my code:
HttpParams params = new BasicHttpParams();
HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
HttpProtocolParams.setContentCharset(params, "UTF-8");
params.setBooleanParameter("http.protocol.expect-continue",false);
HttpClient httpclient = new DefaultHttpClient(params);
HttpGet httpget =new htpGet("http://www.mylink.com"+todaydate);
try
{
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
jsonText = EntityUtils.toString(entity, HTTP.UTF_8);
Log.d("TEST", jsonText); /this is the result string
}
catch (Exception e)
{
}
JSONObject jObj = new JSONObject(jsonText.toString());
Here i cannot convert the string(jsonText) into json object(jobj).But in logcat it is displaying the string jsonText perfectly. Is there any suggestion to get the data as json object.
I need to use the Json object in my application.
If you are certain that the JSON data is valid and no special characters are causing problems then "Unterminated string at character" could mean that you have not received the whole string.
You could prove this by checking a substring from the end and displaying that in logcat
If not then you need to start looking for the special characters again