Develop Reference

How to HTTP POST parameters with Android/Java?

I'm struggling to find good examples on how to POST key value pairs to a URL with Android in Java.
Here is what the Android documentation says (and pretty much every other example):
URL url = new URL(params[0]);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
urlConnection.setDoOutput(true);
urlConnection.setChunkedStreamingMode(0);
OutputStream out = new BufferedOutputStream(urlConnection.getOutputStream());
writeStream(out);
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
readStream(in);
} finally {
urlConnection.disconnect();
}
How do I implement writeStream?
Many other examples with POST put the parameters in the URL (a=1&b=2&c=3...), but then I could just use GET (?). And I don't want to place the parameters in the URL because that increases the chance of sensitive information to be logged on the server side.
Chrome POSTs data as such (body):
------WebKitFormBoundaryyr0AtYZxcOCCp7hA
Content-Disposition: form-data; name="parameterNameHere"
valueHere
------WebKitFormBoundaryyr0AtYZxcOCCp7hA--
Does the Android framework support this?
If not, are there any good libraries?
EDIT:
This is not a duplication of what was suggested. What was suggested does in no way answer the question, in that it does not show how to post with parameters, which is what this question is about.

There are many libraries out there that would help you achieve this. One of the libraries I use the most is OkHTTP. Include this library in your gradle and check the post from 'mauker' for an example on how to post
How to use OKHTTP to make a post request?

How to send special character via HTTP post request made in Java

I need to send data to another system in a Java aplication via HTTP POST method. Using the Apache HttpClient library is not an option.
I create a URL, httpconection without problems. But when sending special character like Spanish Ñ, the system complains it is receiving
Ñ instead of Ñ.
I've read many post, but I don't understand some things:
When doing a POST connection, and writing to the connection object, is it mandatory to do the URLEncode.encode(data,encoding) to the data being sent?
When sending the data, in some examples I have seen they use the
conn.writeBytes(strData), and in other I have seen conn.write(strData.getBytes(encoding)). Which one is it better? Is it related of using the encode?
Update:
The current code:
URL url = new URL(URLstr);
conn1 = (HttpsURLConnection) url.openConnection();
conn1.setRequestMethod("POST");
conn1.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(conn1.getOutputStream());
wr.writeBytes(strToSend);//data sent
wr.flush();
wr.close();
(later I get the response)
strToSend has been previously URLENCODE.encode(,"UTF-8")
I still don't know if I must use urlencode in my code and/or setRequestProperty("Contentype","application/x-www-formurlencode");
Or if I must use .write(strToSend.getByte(??)
Any ideas are welcome. I am testing also the real server (I dont know very much about it)

Jsoup error 502

I'm trying to use jsoup to login to a website (intranet page with some subsystems), enter in a subsystem, search something and parse the page.
I can login, but when I try to access the subsystem I receive an HTTP error 502. However in the browser opens normally.
I think that is some problem with a proxy (which is already set in java). After some few tries my login is blocked and I get the HTTP error 407 (page blocked or something like that)
I already tried to put .useragent("mozilla..."), .timeout(...), .ignorehttperrors(true), ignorecontenttype(true) and using .cookie too.
Is there some way to solve this?
Response x = Jsoup.connect("page").data("...").method(method.GET).execute();
I used the given suggestion (apache httpclient and I don't get the HTTP errors anymore.
But I still want to know if jsoup can bypass this problem, because I could use just one .jar instead 6 (5 from apache plus jsoup to parse the responses.). Thanks to those that who edited my post (rs) and to ollo for the suggestion.

Here's an example using Java's UrlConnection:
URLConnection connection = new URL("your url").openConnection();
connection.addRequestProperty("http.proxyHost", "proxy server");
connection.addRequestProperty("http.proxyPort", "proxy port");
// Alternative:
System.setProperty("http.proxyHost", "yourproxyserver");
System.setProperty("http.proxyPort", "portnumber");
InputStream responseStream = connection.getInputStream();
// Read response into buffer and parse it with jsoup
See also my answer here: JSoup over VPN/proxy
(i guess thats a better one)
But i realy reccommend you HttpClient (or a similar one) for such connection things. As i said before, jsoup as only a limited connection support.

Trying to GET a Google Spreadsheet in Java is returning HTTP error 405

Been working on this all day and have gotten no where with it.
My Java code looks like this:
final URL url = new URL(String.format("https://spreadsheets.google.com/feeds/download/spreadsheets/Export?key=%s&exportFormat=tsv&gid=0", spreadsheetId));
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestProperty("Authorization", "GoogleLogin auth=" + wiseAuth.getAuthToken());
conn.setRequestProperty("GData-Version", "3.0");
conn.setRequestMethod("GET");
conn.setDoOutput(true); // trouble here, see below
conn.setInstanceFollowRedirects(true);
conn.connect();
I always get a FileNotFound error when attempting to do conn.getInputStream(). I narrowed it down to being that the response code is 405 Method Not Allowed. The exception is returning me my URL and I can access the page just fine in my browser.
It was then that I discovered that setDoOutput(true) executes a POST internally. But if I remove that line, conn.getInputStream() is null, and conn.getOutputStream() appears to return nothing--though maybe I am setting it up wrong?

I don't recommend you to do it like this, even if you get it working now you cannot ensure you will get it working in the future if Google started changing it.
Instead, consider using Google Spreadsheet API. The provided Java examples are pretty straightforward and you should able to accomplish what you want.

I would recommend using a web debugger like Fiddler to see what exactly your application is sending in the GET request and compare it to your browser. You might be missing an important header or something, and Fiddler makes it really easy to slowly strip down your browser's request to the essential elements (just drag a request to clone it, then take out headers).

java.io.IOException: Server returns HTTP response code 505

I have HTML based queries in my code and one specific kind seems to give rise to IOExceptions upon receiving 505 response from the server. I have looked up the 505 response along with other people who seemed to have similar problems. Apparently 505 stands for HTTP version mismatch, but when I copy the same query URL to any browser (tried firefox, seamonkey and Opera) there seems to be no problem. One of the posts I read suggested that the browsers might automatically handle the version mismatch problem..
I have tried to dig in deeper by using the nice developer tool that comes with Opera, and it looks like there is no mismatch in versions (I believe Java uses HTTP 1.1) and a nice 200 OK response is received. Why do I experience problems when the same query goes through my Java code?
private InputStream openURL(String urlName) throws IOException{
URL url = new URL(urlName);
URLConnection urlConnection = url.openConnection();
return urlConnection.getInputStream();
}
sample link: http://www.uniprot.org/uniprot/?query=mnemonic%3aNUGM_HUMAN&format=tab&columns=id,entry%20name,reviewed,organism,length

There has been some issues in Tomcat with URLs containing space in it. To fix the problem, you need to encode your url with URLEncoder.
Example (notice the space):
String url="http://example.org/test test2/index.html";
String encodedURL=java.net.URLEncoder.encode(url,"UTF-8");
System.out.println(encodedURL); //outputs http%3A%2F%2Fexample.org%2Ftest+test2%2Findex.html

AS a developer at www.uniprot.org I have the advantage of being able to look in the request logs. In the last year according to the logs we have not send a 505 response code. In any case our servers do understand http 1 requests as well as the default http1.1 (though you might not get the results that you expect).
That makes me suspect there was either some kind of data corruption on the way. Or you where affected by a hardware failure (lately we have had some trouble with a switch and a whole datacentre ;). In any case if you ever have questions or problems with uniprot.org please contact help#uniprot.org then we can see if we can help/fix the problem.
Your code snippet seems normal and should work.
Regards,
Jerven Bolleman

Are you behind a proxy? This code works for me and prints out the same text I see through a browser.
final URL url = new URL("http://www.uniprot.org/uniprot/?query=mnemonic%3aNUGM_HUMAN&format=tab&columns=id,entry%20name,reviewed,organism,length");
final URLConnection conn = url.openConnection();
final InputStream is = conn.getInputStream();
System.out.println(IOUtils.toString(is));
conn is an instance of HttpURLConnection

from the API documentation for the URL class:
The URL class does not itself encode or decode any URL components
[...]. It is the responsibility of the caller to encode any fields,
which need to be escaped prior to calling URL, and also to decode any
escaped fields, that are returned from URL.
so if you have any spaces in your url-str encode it before calling new URL(url-str)

#posdef I was having same HTTP error code 505 problem. When I pasted URL that I was using in Java code in Firefox, Chrome it worked. But through code was giving IOException. But at last I came to know that in url string there were brackets '(' and ')', by removing them it worked so it seems I needed URLEncodeing same like browsers.