I am trying to write a servlet that will send a XML file (xml formatted string) to another servlet via a POST.
(Non essential xml generating code replaced with "Hello there")
StringBuilder sb= new StringBuilder();
sb.append("Hello there");
URL url = new URL("theservlet's URL");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Length", "" + sb.length());
OutputStreamWriter outputWriter = new OutputStreamWriter(connection.getOutputStream());
outputWriter.write(sb.toString());
outputWriter.flush();
outputWriter.close();
This is causing a server error, and the second servlet is never invoked.
This kind of thing is much easier using a library like HttpClient. There's even a post XML code example:
PostMethod post = new PostMethod(url);
RequestEntity entity = new FileRequestEntity(inputFile, "text/xml; charset=ISO-8859-1");
post.setRequestEntity(entity);
HttpClient httpclient = new HttpClient();
int result = httpclient.executeMethod(post);
I recommend using Apache HTTPClient instead, because it's a nicer API.
But to solve this current problem: try calling connection.setDoOutput(true); after you open the connection.
StringBuilder sb= new StringBuilder();
sb.append("Hello there");
URL url = new URL("theservlet's URL");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Length", "" + sb.length());
OutputStreamWriter outputWriter = new OutputStreamWriter(connection.getOutputStream());
outputWriter.write(sb.toString());
outputWriter.flush();
outputWriter.close();
The contents of an HTTP post upload stream and the mechanics of it don't seem to be what you are expecting them to be. You cannot just write a file as the post content, because POST has very specific RFC standards on how the data included in a POST request is supposed to be sent. It is not just the formatted of the content itself, but it is also the mechanic of how it is "written" to the outputstream. Alot of the time POST is now written in chunks. If you look at the source code of Apache's HTTPClient you will see how it writes the chunks.
There are quirks with the content length as result, because the content length is increased by a small number identifying the chunk and a random small sequence of characters that delimits each chunk as it is written over the stream. Look at some of the other methods described in newer Java versions of the HTTPURLConnection.
http://java.sun.com/javase/6/docs/api/java/net/HttpURLConnection.html#setChunkedStreamingMode(int)
If you don't know what you are doing and don't want to learn it, dealing with adding a dependency like Apache HTTPClient really does end up being much easier because it abstracts all the complexity and just works.
Don't forget to use:
connection.setDoOutput( true)
if you intend on sending output.
Related
I am new to REST API and I want to make a REST API call which returns a JSON object
http://smlookup.dev/sec/products?search={"ABC.CP":"123A5"} - Runs fine in a browser and gives a JSON object
how do i get '?search={"ABC.CP":"12345"}' this expression to work as it filter the records
Code i am using is
String serverUrl="http://smlookup.dev/sec/products?search=";
String search=URLEncoder.encode("={\"ABC.CP\":\"12345\"}");
URL url = new URL(serverUrl+search);
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setDoOutput(true);
httpCon.setRequestMethod("GET");
OutputStream out = httpCon.getOutputStream();
//FAILS GIVING 405 STATUS CODE
int responseCode = httpCon.getResponseCode();
All help or suggestions are helpful
Thanks!
Not sure if its normal but you dont send any data in your POST.
Furthermore you should urlencode your url, the inverted comma are not accepted like that.
URLEncoder.encode("={\"Xref.CP\":\"XAW3123A5\"}");
I am sending commands to a server using http, and I currently need to parse a response that the server sends back (I am sending the command via the command line, and the servers response appears in my browser).
There are a lot of resources such as this: Saving a web page to a file in Java, that clearly illustrate how to scrape a page such as cnn.com. However, since this is a response page that is only generated when the camera receives a specific command, my attempts to use the method described by Mike Deck (in the link above) have met with failure. (Specifically, when my program requests the page again the server returns a 401 error.)
The response from the server opens a new tab in my browser. Essentially, I need to know how to save the current web page using java, since reading in a file is probably the most simple way to approach this. Do any of you know how to do this?
TL;DR How do you save the current webpage to a webpage.html or webpage.txt file using java?
EDIT: I used Base64 from the Apache commons codec, which solved my 401 authentication issue. However, I am still getting a 400 error when I attempt to connect my InputStream (see below). Does this mean a connection isn't being established in the first place?
URL url = new URL ("http://"+ipAddress+"/axis-cgi/record/record.cgi?diskid=SD_DISK");
byte[] encodedBytes = Base64.encodeBase64("root:pass".getBytes());
String encoding = new String (encodedBytes);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoInput (true);
connection.setRequestProperty ("Authorization", "Basic " + encoding);
connection.connect();
InputStream content = (InputStream)connection.getInputStream();
BufferedReader in = new BufferedReader (new InputStreamReader (content));
String line;
while ((line = in.readLine()) != null) {
System.out.println(line);
}
EDIT 2: Changing the request to a GET resolved the issue.
So while scrutinizing my code above, I decided to change
connection.setRequestMethod("POST");
to
connection.setRequestMethod("GET");
This solved my problem. In hindsight, I think the server was not recognizing the HTTP because it is not set up to handle the various trappings that come along with post.
Iam creating automated system to post the data to the form for registering into the web site
URL url = new URL("https://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do");
String postData = "firstName="+xlsDataList.get(0)+"&lastName="+xlsDataList.get(1)+"&userName="+xlsDataList.get(2)+"&userNameConfirm="+xlsDataList.get(3)+"&pwd="+xlsDataList.get(5)+"&pwdConfirm="+xlsDataList.get(6);
HttpsURLConnection uc = (HttpsURLConnection) url.openConnection();
uc.setDoInput(true);
uc.setDoOutput(true);
uc.setRequestMethod("POST");
uc.setRequestProperty("Accept", "*/*");
uc.setRequestProperty("Content-Length", Integer.toString(postData.getBytes().length));
uc.setRequestProperty("Content-Type", "text/html; charset=utf-8");
OutputStreamWriter outputWriter = new OutputStreamWriter(uc.getOutputStream());
outputWriter.write(postData);
outputWriter.flush();
outputWriter.close();
I thought that those above postdata are just request attributes , and coded accordingly. But after closely checking the view source, i came to know that those are form attributes.
I dnt have access to that form. Now how can i post the data to the form, so that the user get registered by the site?
i have to set the values to formbean.
Please provide your suggesions.
Your are using the wrong Content-Type in your POST: you need to use application/x-www-form-urlencoded. Once you change that, the server will interpret your request body as request parameters and (likely) your "formbean" will be filled with the data.
The above code may be a test case, but you really ought to take care to properly encode all of your data that you are trying to POST. Otherwise, you run the risk of either having a syntactically invalid request (in which case, the server will either reject the request, or ignore important parameters) or introducing a security vulnerability where a user can inject arbitrary request parameters into your POST. I highly recommend code that looks like this:
import java.net.URLEncoder;
String charset = "UTF-8"; // Change this if you want some other encoding
StringBuilder postData = new StringBuilder();
postData.append(URLEncoder.encode("firstName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(0)), charset);
postData.append("&");
postData.append(URLEncoder.encode("lastName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(1), charset));
postData.append("&");
postData.append(URLEncoder.encode("userName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(2), charset));
postData.append("&");
postData.append(URLEncoder.encode("userNameConfirm", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(3), charset));
postData.append("&");
postData.append(URLEncoder.encode("pwd", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(5), charset));
postData.append("&");
postData.append(URLEncoder.encode("pwdConfirm", charset));
postData.append("=");
postData.append(xlsDataList.get(6), charset));
It seems silly to encode the static strings like "userNameConfirm", but if you get into that habit, you'll end up using it all the time and your code will be a lot safer.
Also, you need to make sure that the data you send through the OutputStream has the right Content-Length: you are computing the content-length properly, but then you aren't using the bytes you used for the computation to send to the client. You want your code to look more like this:
byte[] postDataBytes = postData.getBytes(charset);
uc.setRequestProperty("Content-Length", Integer.toString(postDataBytes.length));
uc.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStream outputStream = uc.getOutputStream();
outputStream.write(postDataBytes);
outputStream.flush();
outputStream.close();
You can find a very comprehensive HTTPUrlConnection tutorial in the community wiki: Using java.net.URLConnection to fire and handle HTTP requests
I recommend to use Apache HttpClient. its faster and easier to implement.
PostMethod post = new PostMethod("https://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do");
NameValuePair[] data = {
new NameValuePair("firstName", "joe"),
new NameValuePair("lastName", "bloggs")
};
post.setRequestBody(data);
InputStream in = post.getResponseBodyAsStream();
// handle response.
For details you can refer http://hc.apache.org/
If your project uses Spring 3.x or later I would recommend using the Spring RestTemplate its pretty handy for doing http, code below will log do a form post.
public String login(String username, String password)
{
MultiValueMap<String, String> form = new LinkedMultiValueMap<>();
form.add(usernameInputFieldName, username);
form.add(passwordInputFieldName, password);
RestTemplate template = new RestTemplate();
URI location = template.postForLocation(loginUrl(), form);
return location.toString();
}
The "HTTP Error 500" you've described in your comment is an "Internal server error".
This means that the server either can't use your request (GET/POST) or there's a problem specific to the server you are trying to call.
Taking a look at the URL you're calling, I immediately the same Error 500.
Same happens for both GET and POST requests at httqs://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do (Live link deactivated; replace "q" with "p" to make it work.)
In short: the generally returned "HTTP Error 500" from WallMart's servers prevents your call to succeed.
By the way:
It's not uncommon to get an error 500 instead of a 403 if they are locking your access down.
As you probably don't own the WallMart website and since you're trying to access levels of their websites that are worth to be protected from 3rd party acces, this might well be the case. ;)
PS: I'm not sure if it's wise to show the AccountLogin number in public like this. After all, it's the client ID of a specific WallMart account holder. But hey, that's your choice, not mine.
Also, double check the parameters you are sending. There may be some validations on input data the server is doing. Eg, some fields are mandatory, some are numbers only, etc.
Try spoofing as a browser by modifying the User Agent. WalMart may have a security mechanism that detects that you are doing this in an automated way.
(If you have problems setting the user agent see this post: Setting user agent of a java URLConnection)
I've read through the other excellent stack overflow articles and tried a lot of them and variations on them but must be making some basic error time and time again? The page I'm posting to works but when I run my java program I just get an empty set on the mySQL database that the data is being posted to. The direct URL that works would be:
http://myURL.co.uk/enteremail.php?email=value
the code
String data = URLEncoder.encode("email", "UTF-8") + "=" + URLEncoder.encode("value1", "UTF-8");
URL url = new URL("http://myURL.co.uk/enteremail.php");
URLConnection conn = url.openConnection();
conn.setRequestMethod("POST");
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
wr.flush();
wr.close();
I know that there are much better ways of doing this using java but I have to use this way as its a bit of a workaround for another problem.
TIA
You need to close the URL connection as well.
I'd suggest checking out the Apache Http client which will do all the heavy lifting for you.
I'd still like to know what was up with my original code, but because what I wanted to do was so simple I've just cut a corner and done this which works for sending the post request to a php page but may not be the solution for anything else:
String email = "myEmail";
URL post= new URL("http://myURL.co.uk/enteremail.php?email="+email);
URLConnection goPost = post.openConnection();
new InputStreamReader(goPost.getInputStream());
Hopefully of some help to someone else down the line, KISS
I have a java application that sends text to a sql database on a server. Currently my java application takes the text, puts it into the url, then sends it to a php page on the server that takes it with GET and puts it in the database. that works fine to an extent, the problem is, that i need to be able to send lots of text, and i keep getting 414, uri to long errors. is there a better way to do this?
ok, i tried what you said, and read the tutorial, but something is not working. here is my code that i tried
public void submitText(String urls,String data) throws IOException{
URL url = new URL(urls);
URLConnection con = url.openConnection();
con.setRequestProperty("Content-Type", "text/plain; charset=utf-8");
con.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
out.write(data);
out.flush();
}
submitText(server + "publicPB.php", "param=" + text);
here is my php code
$param = $_POST['param'];
$sql = "UPDATE table SET cell='{$param}' WHERE 1";
mysql_query($sql);
...
im pretty sure its not a problem with the php as the php worked fine with GET, and thats all i change with it, my problem i think is that im not 100% sure how to send data to it with the java
Use a POST instead of a GET and send the text as the request body. You can only pass so much data to a URL. E.g.:
// Assuming 'input' is a String and contains your text
URL url = new URL("http://hostname/path");
URLConnection con = url.openConnection();
con.setRequestProperty("Content-Type", "text/plain; charset=utf-8");
con.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
out.write(input);
out.close();
See Reading from and Writing to a URLConnection for more details.
Why don't you use POST to send data across to PHP page? GET does have a smaller limit of content.
Use POST requests, which do not have content length limits.
POST requests do not have length content limits and are much secure than GET requests ;)
If using SQL Server I would look into leveraging BCP. You can write the file and call BCP from within Java, and it will send the information directly to your database.