I currently have a project where different parameters are requested from an online CGI file, and each request is supposed to be processed in different threads. When I run my code by itself it works great, however it doesn't seem to connect when I put it in a thread.
My code is below:
public void run() {
connect();
}
public synchronized void connect(){
StringBuffer response = new StringBuffer("");
try {
String data = "year=" + year + "&top=" + numNames + "number=";
// Send data
URL url = new URL("http://www.ssa.gov/cgi-bin/popularnames.cgi");
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
wr.flush();
// Get the response
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line;
while ((line = rd.readLine()) != null) {
response.append(line);
}
wr.close();
rd.close();
} catch (Exception e) {
System.out.println(e);
}
System.out.println(response);
}
}
Remove the synchronized call on connect. That should solve your problem
public synchronized void connect(){
Related
I want to get the result of getServerResult() method but return "null". However, the Logcat inside the httpURLConnectionPost() method is normal which return "sucessful". Please answer me! why I got null outside the httpURLConnectionPost() method with getServerResult() method in this case?
private String serverResult;
public void httpURLConnectionPost(final String urlString){
new Thread(new Runnable() {
public void run() {
try {
URL url = new URL(urlString);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.connect();
String body = stringBuilder();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream(), "UTF-8"));
writer.write(body);
writer.close();
int responseCode = connection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){
InputStream inputStream = connection.getInputStream();
String line;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
while ((line = bufferedReader.readLine()) != null) {
stringBuilderResult.append(line);
}
String result = stringBuilderResult.toString();
Log.d("MSG","result= "+result);
setServerResult(result);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
public void setServerResult(String serverResult){
this.serverResult = serverResult;
}
public String getServerResult(){
return serverResult;
}
D/MSG: result = successful
using getServerResult() :
D/TAG: result = null
Where are you calling httpURLConnectionPost? Regardless you should be using an async task for this, functions that call HTTP requests are not going to return anything because the code is executing and finishing before the response is received.
You need to make sure the task is complete before trying to get any data. Usually you would use an async task and in the onPostExecute portion you would do something to let the app know that data is returned.
I'm a QA with desire to learn more about Java programming and problem I'm experiencing is this:
I'm trying to POST Employee data to the database of some fake Rest API, but I'm getting
Cannot write to a URLConnection if doOutput=false - call
setDoOutput(true)"
So far, I tried some ideas from StackOverflow, but inexperienced as I am, I could easily fall deeper into a problem.
So URL is: http://dummy.restapiexample.com/api/v1/create and firstly I created an Employee class of json object:
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
Employees em = new Employees();
em.setEmployeeName("Alex");
em.setEmployeeSalary("1234");
em.setEmployeeAge("28");
try{
URL url = new URL("http://dummy.restapiexample.com/api/v1/create");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept", "application/json");
if (conn.getResponseCode() != 200) {
throw new RuntimeException("Unsuccessful call: HTTP error : "
+ conn.getResponseCode());
}
// URLConnection urlc = url.openConnection();
// urlc.setDoOutput(true);
PrintWriter pw = new PrintWriter(conn.getOutputStream());
pw.print(new Gson().toJson(em));
pw.close();
pw.flush();
BufferedReader br = new BufferedReader(
new InputStreamReader(conn.getInputStream())
);
String json = "";
String output;
while ((output = br.readLine()) != null) {
json += output;
}
conn.disconnect();
System.out.println("Employee name: " + em.getEmployeeName());
}
catch (MalformedURLException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
Well, using one of your ideas and added next lines of code (it's commented in above code):
URLConnection urlc = url.openConnection();
urlc.setDoOutput(true);
So the code looks like:
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
Employees em = new Employees();
em.setEmployeeName("Alex");
em.setEmployeeSalary("1234");
em.setEmployeeAge("28");
try{
URL url = new URL("http://dummy.restapiexample.com/api/v1/create");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept", "application/json");
if (conn.getResponseCode() != 200) {
throw new RuntimeException("Unsuccessful call: HTTP error : "
+ conn.getResponseCode());
}
URLConnection urlc = url.openConnection();
urlc.setDoOutput(true);
PrintWriter pw = new PrintWriter(urlc.getOutputStream());
pw.print(new Gson().toJson(em));
pw.close();
pw.flush();
BufferedReader br = new BufferedReader(new InputStreamReader(
(urlc.getInputStream())));
String json = "";
String output;
while ((output = br.readLine()) != null) {
json += output;
}
conn.disconnect();
System.out.println("Employee name: " + em.getEmployeeName());
}
catch (MalformedURLException e) {
e.printStackTrace(); }
catch (IOException e) {
e.printStackTrace();
}
}}
With this second code I'm not getting that error, but there is no inserting to the database(checking that using postman, with GET method)...
Well, what am I missing? I guess, I'm missing something basic...
Using url.openConnection twice means you get two different connections. You send the request to the second connection, and try to read the response from the first connection. You should call doOutput on the connection you open originally.
The second problem is you're calling getResponseCode before the request is sent. In http, the request must be sent entirely before the server sends a response. You should move the code that calls doOutput and writes the request body before the code that tries to check the response code.
I'm using Asynctask For network call in android Studio.I have php web API's I dont know why but Some of them Not Working in android .
Following is My AsyncTask Class...
private class AsyncAddfriend extends AsyncTask<String, String, String> {
HttpURLConnection conn;
URL url = null;
#Override
protected String doInBackground(String... params) {
try {
url = new URL("http://ishook.com/users/friends/send_friend_request_json/");
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(READ_TIMEOUT);
conn.setConnectTimeout(CONNECTION_TIMEOUT);
conn.setRequestMethod("POST");
conn.setDoInput(true);
conn.setDoOutput(true);
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("sessionId", params[0])
.appendQueryParameter("UserId", params[1])
.appendQueryParameter("friendId", params[2]);
String query = builder.build().getEncodedQuery();
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
conn.connect();
} catch (IOException e) {
e.printStackTrace();
}
try {
int response_code = conn.getResponseCode();
// Check if successful connection made
if (response_code == HttpURLConnection.HTTP_OK) {
// Read data sent from server
InputStream input = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
StringBuilder result = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
// Pass data to onPostExecute method
return (result.toString());
} else {
return ("unsuccessful");
}
} catch (IOException e) {
e.printStackTrace();
return "exception";
} finally {
conn.disconnect();
}
}
}
I'm using same Code for other API's also they all are working fine but this api is not working.
I have Tested This API in post man its working but in not working android .
Hope You will understand My problem....
I'm trying to use HttpURLConnection for connecting to server from Android app which I'm developing. For now, I'm testing the connection code not in an app but as a plain java program with main class. I guess this doesn't make any difference as far as HttpUrlConnection.
Please examine the code snippet. Another issue is even errorStream is throwing null. This I feel is because of malformed URL.
private static String urlConnectionTry() {
URL url; HttpURLConnection connection = null;
try {
String urlParameters = "email=" + URLEncoder.encode("email", "UTF-8") +
"&pwd=" + URLEncoder.encode("password", "UTF-8");
//Create connection
url = new URL("http://example.com/login");
connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
connection.setRequestProperty("uuid", getUuid());
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setInstanceFollowRedirects(true);
//Send request
DataOutputStream wr = new DataOutputStream (
connection.getOutputStream ());
wr.writeBytes (urlParameters);
wr.flush ();
wr.close ();
//Get Response
InputStream is = connection.getErrorStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer response = new StringBuffer();
while((line = rd.readLine()) != null) {
response.append(line);
response.append('\r');
}
rd.close();
return response.toString();
} catch (Exception e) {
e.printStackTrace();
return null;
} finally {
if(connection != null) {
connection.disconnect();
}
}
}
private static String getUuid() {
try {
Document doc=Jsoup.connect("http://example.com/getUuid").get();
Elements metaElems = doc.select("meta");
for (Element metaElem : metaElems) {
if(metaElem.attr("name").equals("uuid")) {
return metaElem.attr("content");
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
You're probably receiving 401 because the credentials that was sent to the server is not authorized- it's probably not registered or the password is incorrect.
As for the null error stream, take a look at this SO answer.
If the connection was not connected, or if the server did not have an error while connecting or if the server had an error but no error data was sent, this method will return null.
It is probably better if you check first the response code using HttpUrlConnection#getResponseCode(). Decide on whether you'll be checking the contents of the error stream based on the response code you get.
I am using this code to send data to the site where my gae-python app is deployed .But I dont know how to receive it on the other end.
protected void tryLogin(String mUsername, String mPassword)
{
HttpURLConnection connection;
OutputStreamWriter requestself = null;
URL url = null;
String response = null;
String parameters = "username="+mUsername+"&password="+mPassword;
try
{
url = new URL("http://www.pranshutrial3.appspot.com");
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestMethod("POST");
requestself = new OutputStreamWriter(connection.getOutputStream());
requestself.write(parameters);
requestself.flush();
requestself.close();
String line = "";
InputStreamReader isr = new InputStreamReader(connection.getInputStream());
BufferedReader reader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
// Response from server after login process will be stored in response variable.
response = sb.toString();
// You can perform UI operations here
Toast.makeText(this,"Message from Server: \n"+ response, Toast.LENGTH_LONG).show();
isr.close();
reader.close();
}
catch(IOException e)
{
// Error
}
}