I'm trying to send data from an Android smartphone via a POST request to a REST web service.
There is no error on client side, but on the server side is no code executed if I have sent the data:
Client:
public void connect2server(View v) throws IOException {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://192.168.1.108:8182");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("stringdata", "data"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
Server side:
public class data_server extends ServerResource {
public static void main(String[] args) throws Exception {
// Create the HTTP server and listen on port 8182
new Server(Protocol.HTTP, 8182, data_server.class).start();
}
#Post
public String toString1() throws IOException {
System.out.println(getRequestEntity().getText());
return "ok";
}
}
How is this caused and how can I solve this?
There's no error because you are catching the errors and doing nothing with them.
Try adding the following into the catch blocks and you should see what's happening in your LogCat output. Remember to the import the Log class
Log.w("com.name.pkg", e);
where "com.name.pkg" is just a tag so help you filter on. usually the name of the program.
Alternatively, quite commonly in use is to send a toast with Toast.makeText(...).show(); with e.getMessage() but I don't like doing that, so I don't recommend it. You would be better to pass a string back to the calling function and allow that to do the toast.
Related
How to send a simple http command without opening the browser??
public void addListenerOnButton() {
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
Intent browserIntent =
new Intent(Intent.ACTION_VIEW, Uri.parse("http://192.168.1.95:8080/json.htm?type=command¶m=switchlight&idx=2&switchcmd=Off&level=0"));
startActivity(browserIntent);
}
});
I think, I know what you want to do. A simple example here, could be helpful.
HTTPClient is what you are looking for. Make sure to use it in a background thread, e.g. in an AsyncTask.
A tutorial like this will get you started: http://hmkcode.com/android-internet-connection-using-http-get-httpclient/
The same question Make an HTTP request with android
Simply, here is the code ( http://www.androidhive.info/2011/10/android-making-http-requests/ )
// Creating HTTP client
HttpClient httpClient = new DefaultHttpClient();
// Creating HTTP Post
HttpPost httpPost = new HttpPost(
"http://www.example.com/login");
// Building post parameters
// key and value pair
List<NameValuePair> nameValuePair = new ArrayList<NameValuePair>(2);
nameValuePair.add(new BasicNameValuePair("email", "user#gmail.com"));
nameValuePair.add(new BasicNameValuePair("message",
"Hi, trying Android HTTP post!"));
// Url Encoding the POST parameters
try {
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePair));
} catch (UnsupportedEncodingException e) {
// writing error to Log
e.printStackTrace();
}
// Making HTTP Request
try {
HttpResponse response = httpClient.execute(httpPost);
// writing response to log
Log.d("Http Response:", response.toString());
} catch (ClientProtocolException e) {
// writing exception to log
e.printStackTrace();
} catch (IOException e) {
// writing exception to log
e.printStackTrace();
}
I have a backend for my android app, which returns 404 on GET and json on POST. Now, I'm trying to do POST request using this snippet:
public void postData() {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/api/login");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("email", "email#email.com"));
nameValuePairs.add(new BasicNameValuePair("password", "qwerty"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
Server however receives GET request. With curl POST backend returns json as expected. But somehow httpPost sends GET(!) request. What could be the problem? What am I doing wrong?
Ok guys, answered my own question pretty quickly, may be helpful for others.
I replaced hostname with ip address, and it worked!
i am new to android, i m trying to api call with php , i have done one example for it, that work on another computer fine but same app package gives error in eclipse on my laptop.
public void postData() {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("stringdata", "Hi"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
} `
hear is my error log, i got this much of errors.
//Try following way
//List<NameValuePair> nameValuePairs
HttpClient hc = new DefaultHttpClient();
HttpPost hp = new HttpPost(url);
UrlEncodedFormEntity obj=new UrlEncodedFormEntity(nameValuePairs);
obj.setChunked(true);
hp.setEntity(obj);
HttpResponse hr = hc.execute(hp);
HttpEntity he = hr.getEntity();
Logcat is clear: Could not find a method postData(View) in the activity class. I guess you've used xml layout for setting button action.
In this case, just change your
public void postData() {
}
to
public void postData(View view) {
}
Note: setting button listeners this way isn't efficient.
Also, you should perform network operations on another thread - using network on main thread will raise NetworkOnMainThreadException on Android 3.0+
I have just a curiosity question. I have an HttpPost request in Android that looks something like this:
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(getString(R.string.url));
//This code does not work
HttpParams params = new BasicHttpParams();
params.setParameter("type", "20");
post.setParams(params);
try {
HttpResponse response = client.execute(post);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
On my server side, I have a servlet that listens for requests and parses the parameters:
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Enumeration en = request.getParameterNames();
while (en.hasMoreElements()){
System.out.println(en.nextElement());
}
}
When I execute this code, the servlet does not see any parameters at all. But if I replace the whole "parameter" chunk with this code:
//This code works
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(5);
nameValuePairs.add(new BasicNameValuePair("type", "20"));
try {
post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
My servlet can parse parameters. It's not a problem, I'm just going to use the entity but my question is, why can't my servlet getthe parameters from the first code chunk? What's wrong with setParams? Why can the servlet see parameters if I make them an entity?
In HTML when we have something like "http://host/path?user=uname&passwd=pass", we call the part (user=uname&passwd=pass) after the question mark "form data".The "form data" can be attached to the end of the URL after a question mark (as above), for GET requests, or sent to the server on a separate line, for POST requests.The "form data" are split to parameters. The parameters are separated by & when we use GET.
In our case the HttpPost and HttpGet classes extend the AbstractHttpMessage which implements the setParams method. This method is same for GET and POST but does the job only for GET! In the case of GET the parameters are put in the URL. In the case of POST you need to set the entity for the parameters to be on a "separate line".
On the server side when using servlets the getParameters is clever enough to find the parameters for GET and POST.
Thats why on the server side we do not need to change the code for getting the parameters!
Hope I helped!
can anyone give me an idea of using web service using HTTP protocol.
Here is an example for "Executing a HTTP POST Request with HttpClient":
public void postData() {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "123"));
nameValuePairs.add(new BasicNameValuePair("username", "Paresh"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
We can use web services in our application to send and receive data from a remote server. Consider the case of an login section from a application where you need to pass username and password to the server for checking the whether the user is a valid user or not. In this case the username and password are attached with a url and send it to the remote server for validation and in response you get a value stating whether the user is a valid user or not. Usually the response will be either in XML format or JSON format from there we need to parse that response to get the necessary values. Check out the following example code in this I have created a class named "parsing" and it using the http protocol to receive a data.
public class parsing extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
HttpClient client = new DefaultHttpClient();
String postURL = "http://services.digg.com/topics?appkey=http://example.com&type=json";
HttpPost post = new HttpPost(postURL);
HttpResponse responsePOST = client.execute(post);
HttpEntity resEntity = responsePOST.getEntity();
String response=EntityUtils.toString(resEntity);
response=response.trim();
Log.i("RESPONSE=",response);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
See the response on the Logcat and do not for get to include <uses-permission android:name="android.permission.INTERNET" />
because we are fetching the data from the remote server which needs internet permission.