I am using the following code to get a JSON object from a URL :
public JSONObject makeRequest(String url) throws IOException, JSONException {
JSONObject response;
String jsonString;
HttpClient httpclient = new DefaultHttpClient();
// create the request
HttpUriRequest request = new HttpGet(url);
request.addHeader("Accept-Encoding", "gzip");
// execute the request
HttpResponse resp = httpclient.execute(request);
StatusLine statusLine = resp.getStatusLine();
// check the request response status. Should be 200 OK
if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
Header contentEncoding = resp.getFirstHeader("Content-Encoding");
InputStream instream = resp.getEntity().getContent();
// was the returned response gzip'ed?
if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {
instream = new GZIPInputStream(instream);
}
BufferedReader reader = new BufferedReader(new InputStreamReader(instream));
StringBuilder responseString = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
responseString.append(line);
}
jsonString = responseString.toString();
response = new JSONObject(jsonString);
} else {
resp.getEntity().getContent().close();
throw new IOException(statusLine.getReasonPhrase());
}
return response;
}
But I get an error saying bad request on this line :
throw new IOException(statusLine.getReasonPhrase());
and the result is not returned.
How do I fix this ?
Thanks !
Try to use this code instead. Much simplified.
try {//Making a request to server getting entities
JSONObject json = new JSONObject(EntityUtils.toString(new DefaultHttpClient().execute(new HttpGet(URL)).getEntity()));
//getting json root object
JSONObject obj = json.getJSONObject("ROOT_ELEMENT");
} catch (JSONException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Related
I am currently learning to develop android application. I need to parse variables from my android application to the servlet. I use HttpResponse to parse the variables. But i do not know how to accept parameters in servlet.
This is my code in android application.
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://<ip_address>:8080/GetPhoneNumber/GetPhoneNumberServletServlet");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("phoneNum", "12345678"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} // End of onClick method
May I know what to do at the doPost/doGet in servlet?
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter out = response.getWriter();
out.println("Hello Android !!!!");
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
In your doPost use request.getParameter("phoneNum").
I think the following code could help you.
public class CustomHttpClient
{
public static final int HTTP_TIMEOUT = 30 * 1000;
private static HttpClient mHttpClient;
private static HttpClient getHttpClient()
{
if (mHttpClient == null)
{
mHttpClient = new DefaultHttpClient();
final HttpParams params = mHttpClient.getParams();
HttpConnectionParams.setConnectionTimeout(params, HTTP_TIMEOUT);
HttpConnectionParams.setSoTimeout(params, HTTP_TIMEOUT);
ConnManagerParams.setTimeout(params, HTTP_TIMEOUT);
}
return mHttpClient;
}
public static String executeHttpPost(String url,ArrayList<NameValuePair> postParameters) throws Exception
{
BufferedReader in = null;
try
{
HttpClient client = getHttpClient();
HttpPost request = new HttpPost(url);
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);
request.setEntity(formEntity);
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
String result = sb.toString();
return result;
}
finally
{
if (in != null)
{
try
{
in.close();
}
catch (IOException e)
{
Log.e("log_tag", "Error converting result "+e.toString());
e.printStackTrace();
}
}
}
}
public static String executeHttpGet(String url) throws Exception
{
BufferedReader in = null;
try
{
HttpClient client = getHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(url));
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
String result = sb.toString();
return result;
}
finally
{
if (in != null)
{
try
{
in.close();
}
catch (IOException e)
{
Log.e("log_tag", "Error converting result "+e.toString());
e.printStackTrace();
}
}
}
}
}
Addons:-
Use the JSON Parser class below:-
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.d("json data",json.toString());
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
Now if you want to send anything on the server, say you need to save the username and password on the server using the JSON Parser and PHP use the below code in any thread or in the doInBackground method of Async task.
ArrayList<NameValuePair> Insert = new ArrayList<NameValuePair>();
Insert.add(new BasicNameValuePair("User_Name","<Sting denoting username>"));
Insert.add(new BasicNameValuePair("Password","<Sting denoting Password>));
try
{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://server path/yourphpfile.php");
httppost.setEntity(new UrlEncodedFormEntity(Insert));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}
catch(Exception e)
{
Log.e("log_tag", "Error in http connection"+e.toString());
}
Now if you need these values back using the get method in JSON Parser, user the following code again in the Thread or doInBackground method of Async task.
public class CountDownTask extends AsyncTask<Void,Void , Void>
{
protected void onPreExecute()
{
count = 0;
S_Store_Id = null; S_Store_Name = null;S_Store_Address = null; S_Store_Phone= null;
Offers = null; Descriptions = null;
}
protected Void doInBackground(Void... params)
{
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("User_Name",StringUserName));
String response = null;
try
{
response = CustomHttpClient.executeHttpPost("http://yourserverpath/yourphpfilefor retrivingdata.php",postParameters);
String result = response.toString();
try
{
JSONArray jArray = new JSONArray(result);
JSONObject json_data = jArray.getJSONObject(0);
StringUserName = json_data.getString("User_Name");
StringPassword = json_data.getString("Password");
json_data = jArray.getJSONObject(1);
}
catch(JSONException e)
{
Log.e("log_tag", "Error parsing data "+e.toString());
}
}
catch (Exception e)
{
Log.e("log_tag","Error in http connection!!" + e.toString());
}
return null;
}
Now you can write the logic for inserting and retriving data from the server in your corresponding PHP files and use them for using data from the server. This method works equivalent to HTTP Get and Post methods of HTTP Request and Response.
Hope it can help you.. Thanks...
I have an application that post data to a php file in an online server. When the post is done i get a garbage of html code. In it says I have a php error and that is Invalid argument supplied for each() on line 33. However this problem does not occur if I run it in localhost. I don't understand why this problem is occuring. So someone please help me to solve it.
The following is my jsonparser Class
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getandpostJSONFromUrl(String url, String method,JSONArray name) {
// Making HTTP request
try {
// defaultHttpClient
if (method == "POST") {
HttpParams params = new BasicHttpParams();
//params.setParameter("data", auth);
HttpClient httpclient = new DefaultHttpClient(params);
HttpPost httpPost = new HttpPost(url);
List<NameValuePair> postParams = new ArrayList<NameValuePair>();
postParams.add(new BasicNameValuePair("json", name.toString()));
for (NameValuePair nvp : postParams) {
String name2 = nvp.getName();
String value = nvp.getValue();
Log.d("NameValue pair content", ""+name2+""+value);
}
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postParams,HTTP.UTF_8);
httpPost.setEntity(entity);
HttpResponse response = httpclient.execute(httpPost);
String responseBody = EntityUtils.toString(response.getEntity());
Log.d("",responseBody);
}
if (method == "GET") {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (method == "POST") {
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is));
} catch (Exception e) {
Log.e("Buffer error", "Buffer error" + e);
}
} else if (method == "GET") {
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
}
// return JSON String
return jObj;
}
}
The following is the php file on the server
<?php
header('Content-type: application/json');
/*define('DB_NAME', 'a1422982_sshop');
define('DB_USER', 'root');
define('DB_PASSWORD', '');
define('DB_HOST', 'localhost');*/
define('DB_NAME', 'onlineshop');
define('DB_USER', 'shop');
define('DB_PASSWORD', 'pass');
define('DB_HOST', 'mysql28.000webhost.com');
$link = mysql_connect(DB_HOST,DB_USER,DB_PASSWORD);
if(!$link){
die('could not connect: '.msql_error());
}
$db_selected=mysql_select_db(DB_NAME, $link);
if(!$db_selected){
die('Can not use '.DB_NAME.':'.mysql_error());
}
//var_dump(json_decode ($_POST['json'])));
if($_POST['json']){
$parsed = json_decode($_POST['json'],TRUE);
$i=0;
foreach ($parsed as $obj) {
$ProductName = $obj['Name'];
$ProductQuantity= $obj['Quantity'];
$sql="Update productlist Set Quantity='$ProductQuantity' where Name='$ProductName';";
$retval = mysql_query( $sql, $link );
if(! $retval )
{
die('Could not get data: ' . mysql_error());
}
$i++;
echo $ProductName." ".$ProductQuantity;
}
}else{
echo "empty";
}
?>
there's a missing options on your HttpPost request set the entity metadata and the resulting entity as string.
In your java code you can do this:
Map<String, String> postData = new HashMap<String, String>();
postData.put("KEY", "yourvalue");
JSONObject holder = new JSONObject(postData);
StringEntity jsonStringEntity = new StringEntity(holder.toString());
httpost.setEntity(jsonStringEntity);
httpost.setHeader("Accept", "application/json");
httpost.setHeader("Content-type", "application/json");
in that way your PHP code could actually parse your post data since json_decode() expecting json as parameter.
I'm trying to parse JSON data which is coming from this url.
But I am getting these errors:
03-27 16:48:21.019: E/Buffer Error(23717): Error converting result java.lang.NullPointerException
03-27 16:48:21.059: E/JSON Parser(23717): Error parsing data org.json.JSONException: End of input at character 0 of
Wwhen I debug my code; getJsonFromUrl() method returns null jobject. Here is the JSONParser class which I used. What's causing the error?
public class JSONParser {
static InputStream iStream = null;
static JSONArray jarray = null;
static JSONObject jObj= null;
static String json = "";
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
try {
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
InputStream is = httpEntity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
iStream.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parsing the string to a JSON object
try {
if (json != null) {
jObj = new JSONObject(json);
} else {
jObj = null;
}
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
I'm making the call for this method from another class using these lines. (url parameter is defined at top)
JSONParser jParser = new JSONParser();
final JSONObject jobject = jParser.getJSONFromUrl(url);
You are trying to get the JSON content using a HTTP POST method instead of the appropiated GET method (W3schools.com GET vs.POST), modify your source code to simplify and fix your HTTP request
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet get = new HttpGet(url);
try {
HttpResponse httpResponse = httpClient.execute(get);
String json = EntityUtils.toString(httpResponse.getEntity());
System.out.println(json);
....
....
} catch (Exception e) {
....
}
I have to make a http Post request using a JSON string I already have generated.
I tried different two different methods :
1.HttpURLConnection
2.HttpClient
but I get the same "unwanted" result from both of them.
My code so far with HttpURLConnection is:
public static void SaveWorkflow() throws IOException {
URL url = null;
url = new URL(myURLgoeshere);
HttpURLConnection urlConn = null;
urlConn = (HttpURLConnection) url.openConnection();
urlConn.setDoInput (true);
urlConn.setDoOutput (true);
urlConn.setRequestMethod("POST");
urlConn.setRequestProperty("Content-Type", "application/json");
urlConn.connect();
DataOutputStream output = null;
DataInputStream input = null;
output = new DataOutputStream(urlConn.getOutputStream());
/*Construct the POST data.*/
String content = generatedJSONString;
/* Send the request data.*/
output.writeBytes(content);
output.flush();
output.close();
/* Get response data.*/
String response = null;
input = new DataInputStream (urlConn.getInputStream());
while (null != ((response = input.readLine()))) {
System.out.println(response);
input.close ();
}
}
My code so far with HttpClient is:
public static void SaveWorkflow() {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost(myUrlgoeshere);
StringEntity input = new StringEntity(generatedJSONString);
input.setContentType("application/json;charset=UTF-8");
postRequest.setEntity(input);
input.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE,"application/json;charset=UTF-8"));
postRequest.setHeader("Accept", "application/json");
postRequest.setEntity(input);
HttpResponse response = httpClient.execute(postRequest);
BufferedReader br = new BufferedReader(
new InputStreamReader((response.getEntity().getContent())));
String output;
while ((output = br.readLine()) != null) {
System.out.println(output);
}
httpClient.getConnectionManager().shutdown();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Where generated JsonString is like this:
{"description":"prova_Process","modelgroup":"","modified":"false"}
The response I get is:
{"response":false,"message":"Error in saving the model. A JSONObject text must begin with '{' at 1 [character 2 line 1]","ids":[]}
Any idea please?
Finally I managed to find the solution to my problem ...
public static void SaveWorkFlow() throws IOException
{
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPost post = new HttpPost(myURLgoesHERE);
List<NameValuePair> params = new ArrayList<>();
params.add(new BasicNameValuePair("task", "savemodel"));
params.add(new BasicNameValuePair("code", generatedJSONString));
CloseableHttpResponse response = null;
Scanner in = null;
try
{
post.setEntity(new UrlEncodedFormEntity(params));
response = httpClient.execute(post);
// System.out.println(response.getStatusLine());
HttpEntity entity = response.getEntity();
in = new Scanner(entity.getContent());
while (in.hasNext())
{
System.out.println(in.next());
}
EntityUtils.consume(entity);
} finally
{
in.close();
response.close();
}
}
Another way to achieve this is as shown below:
public static void makePostJsonRequest(String jsonString)
{
HttpClient httpClient = new DefaultHttpClient();
try {
HttpPost postRequest = new HttpPost("Ur_URL");
postRequest.setHeader("Content-type", "application/json");
StringEntity entity = new StringEntity(jsonString);
postRequest.setEntity(entity);
long startTime = System.currentTimeMillis();
HttpResponse response = httpClient.execute(postRequest);
long elapsedTime = System.currentTimeMillis() - startTime;
//System.out.println("Time taken : "+elapsedTime+"ms");
InputStream is = response.getEntity().getContent();
Reader reader = new InputStreamReader(is);
BufferedReader bufferedReader = new BufferedReader(reader);
StringBuilder builder = new StringBuilder();
while (true) {
try {
String line = bufferedReader.readLine();
if (line != null) {
builder.append(line);
} else {
break;
}
} catch (Exception e) {
e.printStackTrace();
}
}
//System.out.println(builder.toString());
//System.out.println("****************");
} catch (Exception ex) {
ex.printStackTrace();
}
}
i have a simple JSON feed which returns an image path, and a set of coordinations. The "coords" can have an unlimited set of coordinations. In my example below it only has 3 set.
{"image":"Some data", "coords": {"0":[0,0], "1":[55,22], "2":[46,65]}}
How would i use GSON to parse this? How do I build the class for this?
Thanks
You're going to have a hard time with that because it's not valid JSON.
http://jsonlint.com/
If it were valid JSON such as ...
{"image":"Some data", "coords": {"0":[0,0], "1":[55,22], "2":[46,65]}}
I believe GSON could parse coords to a map of <String, ArrayList<Integer>> but I'd need to try it to make sure.
Add the gson-1.7.1.jar file and write this class to get the required JSONObject or JSONArray from the url.
public class GetJson {
public JSONArray readJsonArray(String url) {
String read = null;
JSONArray mJsonArray = null;
try {
HttpClient http = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
HttpResponse response = http.execute(post);
HttpEntity entity = response.getEntity();
InputStream is = entity.getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuilder builder = new StringBuilder();
String str = null;
while ((str = br.readLine()) != null) {
builder.append(str);
}
is.close();
read = builder.toString();
mJsonArray = new JSONArray(read);
} catch (Exception e) {
e.printStackTrace();
}
return mJsonArray;
}
public JSONObject readJsonObject(String url) {
String read = null;
JSONObject mJsonObject = null;
try {
HttpClient http = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
HttpResponse response = http.execute(post);
HttpEntity entity = response.getEntity();
InputStream is = entity.getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuilder builder = new StringBuilder();
String str = null;
while ((str = br.readLine()) != null) {
builder.append(str);
}
is.close();
read = builder.toString();
mJsonObject = new JSONObject(read);
} catch (Exception e) {
e.printStackTrace();
}
return mJsonObject;
}
}
ENJOY...
Then to parse the JSON see the these tutorials,
Tutorial 1
Tutorial 2
Tutorial 3