I need to implement a servlet that uploads files to a server, I realize everyone says it has to be a POST method in regard to uploading files and not with GET method. However is there a way to upload a file and have the parameters of the request show up in the url even if the request is coming from POST method? If not, is there another approach?
Currently my servlet using post method is http://example.com/FileUpload/UploadFile
What I want is somehting like http://example.com/FileUpload/UploadFile?id=125&fileNum=5
Thanks for your input.
Simply POST to
http://example.com/FileUpload/UploadFile?id=125&fileNum=5
instead of
http://example.com/FileUpload/UploadFile
There is no such restriction that you cannot post to an URL having parameters. You can process the post data as you are doing now, plus, you can get the get parameters also.
I think it would not be an elegant solution, but you could use JavaScript to alter the action of the form element before submitting it to include querystring parameters.
The form will be something like:
<form method="POST" id="myForm" onSubmit="submitMyForm(this)>
<input type="text" id="id">
Then you will need JavaScript to change the action element of the form:
function submitMyForm(theForm) {
theForm.action="http://example.com/FileUpload/UploadFile?id=" +
getElementById("id").value;
theForm.submit();
}
Is there some reason you cannot just submit the parameters with post and pull them out on the server side?
Alternatively, if you do a multipart/form-data post you can include multiple parameters along with your file. The parameters are sent as part of the post body, along with the file.
You can send parameters and files in the POST. For example in the html you can have a form with this values, they can be of hidden type.
In the servlet you can get the values in the same way you do using the GET.
It is also better to use the POST method because the user can't change the value in the URL direction bar.
Related
So I'm trying to log in to a webpage using Jaunt. The first thing to mention is that the webpage is .aspx and the submit button has an option onclick="javascript:WebForm_DoP..." and as far as I know Jaunt doesn't support Javascript right?
In case I'm wrong, the code I'm using is the one in the examples of Jaunt:
Form form = userAgent.doc.getForm(0);
form.setTextField("Login1$UserName","USER");
form.setPassword("Login1$Password","PASSWORD");
form.setCheckBox("Login1$RememberMe",false);
form.submit("GO");
System.out.println(userAgent.getLocation());
All the names and values are correct, and the user and password works since I can log in using the web browser. After I execute the code, in the output I get this:
message: UserAgent.sendPOST; Connection error requestUrl:
http://webpagehere.com/default.aspx [posting
__VIEWSTATE=%2FwEPDwUJLTk5MDc0NjQ2ZBgBBR5fX0NvbnRyb2xzUmVxdWlyZVBvc3RCYWNrS2V5X18WAgURTG9naW4xJFJlbWVtYmVyTWUFF0xvZ2luMSRMb2dpbkltYWdlQnV0dG9upWcarODJIwpeMt8HCmfaBn6iMWI%3D&__VIEWSTATEGENERATOR=CA0B0334&Login1%24UserName=USER&Login1%24Password=PASSWORD&Login1%24LoginButton=GO]
response: [none]
The form div is this one:
<form name="form1" method="post" action="Default.aspx" onsubmit="javascript:return WebForm_OnSubmit();" id="form1" style="text-align:center">
Any ideas what could be my problem? In case Jaunt doesn't allow me to do this login, could someone please recommend me a library for web scraping and interaction? Thanks!
Seems like you are stuck. Actually .aspx pages uses AJAX pagination. You will have to extract the values of __VIEWSTATE, __VIEWSTATEGENERATOR and all other form values and then send them with POST method in the request body. You can use Fiddler to get the request body which contains all these hidden variables and your entries to the form.
In Java you can use Selenium Or HTMLUnit which are Java GUI-Less browser, supporting JavaScript, to run agains web pages.
edit: You can use Jaunt-api as well, I just tried it with it, all you do is send a POST request alongwith the request-body, you can easily check it with Fiddler, and it works!!
Form values in HTTP POSTs are sent in the request body, in the same format as the querystring. You can find the request body of a link by inspecting it using the Fiddler and then copy request body from Textview and send the encoded data as request body.
UserAgent userAgent = new UserAgent();
userAgent.sendPOST("<your link to form page>","<request body>");
I am analayising the existing project, in one of the JSP page I saw that
String server=request.getParameter("server");
But I am trying to check How I can find where is this server parameter is set
I searched for setParameter("server"), no luck
can any one suggest on this
Main idea, I need to change the values for the values which is set in "server" parameter.
You can look in any of HTML elements, where they may have tag like <input type='text' id='server' name='server' /> like that. I have given example of text box, it can be anything.
And no, there is no such method called request.setParameter()
You can get this attribute from the html/jsp page from where the form is being submitted.
It is set by the HTTP request that was generated by the client side (such as a browser). For example, an HTML form, upon submission, would result in an HTTP request with parameters for each field. A standalone client (non-browser) can set request parameters by merely adding those parameters to the URL itself.
Therefore, first you have to determine what is generating the HTTP request that results in your JSP page being called. Once you find who's generating the request, it will be very easy for you to find how the parameter itself is set.
In your web.xml first check, from which form present in JSP/HTML the request is coming.
In the corresponding action, you will get all the input fields in the form, which will be fetched in the servelet through request.getParameter('')
This parameter is set when any form is submitted. Check the page which calls this servlet. That page will contain a form having field like <input type='text' name='server' />. If not found then check URL query parameter.
EDIT
In web.xml check which URL is being mapped to your servlet.
In my JSP page I have DIV.
<div id="100">
ALI
</div>
When I click on this DIV...
$("#100").click(function(){
});
...I need to send the value of the id 100, to a servlet, so that the servlet makes some database java codes, and returns for example, either 1 or 0. How can I do that? and is this the proper way?
Using Ajax, you should call your server using a URL similar to this:
http://localhot:8080/youAppContext/yourServer?id=100
Then, in the servler side, you should retrieve the value that will be in the request with the name "id"
There are out there many tool as jQuery that can help you to do the Ajax petition.
Edited
Well, here you can find a very simple Ajax example using jQuery. In the example, instead call a file (test1.txt) you should invoke a URL (as I described above). Of course, you will need to write some JS code to build your URL (where id be a variable). Once task is done in servlet side, you can return whatever, for example: "done" and display or not this information the HTML as it is done in the example.
Take a look to this Web, there are many links that can help you.
get the value using
var value = $("#100").html();
and pass it to servlet using AJAX
I have a login form with username and password. It works, but after the request I see on the web browser something like "...login?user=myUser&password=myPassword".
Given that the form has a password field that hides the password while it's typed, it would not be funny to see the password on the address bar.
Is it possible to avoid this?
The user verification is done on the server with a custom java web server.
Set your HTTP form method to a POST, instead of a GET. This eliminates the form to append the parameters on the url.
Secure your page to use HTTPS instead of HTTP. That way, an eavesdropper cannot read unencrypted HTTP POST message.
The only way that this can be done is by not using the GET method of form submission. You need to use the POST method. More information can be found here http://www.cs.tut.fi/~jkorpela/forms/methods.html
Your form will look like this
<form method="post" action="somepage.php">
</form>
Your form is using the GET not POST. Passing variables via a query-string in the URL (GET) can be dangerous as users can see and modify these values. Change your form's method to POST. In standard HTML this would look like:
<form method="GET" action="......
...to...
<form method="POST" action=".....
You can encode the password, which will obscure it.
However using a POST form instead will hide all its fields.
Yes, use a POST request instead of GET.
Convert your form to use the HTTP "POST" method instead of "GET", e.g.:
<form action="/login" method="post">
Also consider obscuring the password before it is transmitted, e.g. using a scheme such as Base64 or MD5.
Change the 'method' attribute on the form from "get" to "post" -- and send the request over HTTPS, preferably.
When you see a "login?user=myUser&password=myPassword" in your address bar this means that your Login form is using the GET request method:
<form id="login" action="some_file" method="get">
The easiest way of hiding this info would be to change from GET to POST method:
<form id="login" action="some_file" method="post">
You can read more about both of these methods here:
When to use POST and GET?
However, note that POST is not much safer than GET. You can read more about this here:
POST and GET in terms of Security
I've created a form and I need the user to enter some info then upload a picture.
So lets say I have something like this:
<form method="post" enctype="multipart/form-data" action="some servlet/filter">
<input type="file" name="logo">
</form>
I need to use java to change that data to a byte[] then to blob so I can insert to a table.
How do I get the data from this form?
A bit of info on this:
I created the page using javascript, then when submitted it will call a java function to handle the data from the form. It seems that when I submit the form the data for the file is not passed over to the servlet.
So far the few methods I've tried have returned null and I'm outta ideas...
Any examples/help is greatly appreciated!
I think the main question I have is where is the file data stored before the java file start working on it? Is a special global variable holding the data or something like that?
You can use the Apache Commons FileUpload library.
The Commons FileUpload package makes it easy to add robust, high-performance, file upload capability to your servlets and web applications.
FileUpload parses HTTP requests which conform to RFC 1867, "Form-based File Upload in HTML". That is, if an HTTP request is submitted using the POST method, and with a content type of "multipart/form-data", then FileUpload can parse that request, and make the results available in a manner easily used by the caller.
If I understood you right, you need something similar to this example:
http://www.servletworld.com/servlet-tutorials/servlet-file-upload-example.html
I used the following tutorial one year ago:
http://balusc.blogspot.com/2009/12/uploading-files-in-servlet-30.html
It looks like it's a lot, but it's actually easy to understand, and it has a lot of good information.