My problem is when I'm trying to access a POST Variable with request.getParameter("name"), it works perfectly. But in some conditions, when a POST request arrives at my application, I also need to get GET Parameter from the Query String.
As far as I can see, with getParameter, you can only access current request's parameters, but, as in my condition, as I said, I also need to fetch GET Parameters inside doPost method.
Is there a way to fetch GET Parameters without parsing the Query String?
If you have parameters with the same name in the query string and in the posted form data, use getParameterValues().
Example:-
String fromQuery = request.getParameterValues("name")[0];
String fromForm = request.getParameterValues("name")[1];
The getParameter() method can return (if possible) both GET and POST parameters as it works transparently between GET and POST. You don't need to do any explicit work to get the GET parameters. you can use getParameter for both query parameters and POST parameters.
But should you do it? - It's considered a poor design practice especially if there is sensitive information to be sent.
Take a look at this answer:
HTTP POST with URL query parameters -- good idea or not?
I think you have a confusion here. You can retrieve all the request parameters (in both GET or POST or others) using the same getParameter(..) depending upon the type of request. If it's a GET request, you can retrieve all the GET parameters.
If it's a POST request, you can retrieve all the POST parameters. You get parameters using getParameter(...). And you make one request at a time. If you make a POST request in html or JSP file, you use doPost method receive all the parameters. At this point, there is nothing in GET request. Then after that, you make a GET request, you retrieve all the parameters in doGet method. At this moment, there is nothing in POST. Remember, HTTP requests are stateless.
To complete #Rei answer check out this code :
your form
<form action="?nom=nom1">
<input type="hidden" name="nom" value="nm2"/>
your doPost
System.out.println(request.getParameter("nom"));
String s = "";
for(String ss : request.getParameterValues("nom")) {
s += "|" + ss;
}
System.out.println(s);
System.out.println(request.getParameterMap().get("nom"));
what will be printed
nom1
|nom1|nm2
[Ljava.lang.String;#c7068db
ps : thanks to Julien for the code and testing
Related
I was given this as an in class problem and recievd 0 as the result, but I can't find the fault with it. The questions is Write the lines of code you would need to use in a servlet to retrieve a parameter
from an incoming request and add it to the session as an attribute:
My answer:
String param1= request.getParameter("param1");
HttpSession session= request.getSession();
String parameter1= (String)request.getAttribute("param1");
session.setAttribute("param1", parameter1);
Also, is the '(String)' necessary in the second line? or just good practice?
Thanks :)
You've made a very common mistake, confusing attributes with parameters. In your code you have:
String parameter1= (String)request.getAttribute("param1");
Attributes can be thought of as meta-data of the request. For example, if the request is made via SSL then you can get data about the request from the attributes. Take a look at the documentation for getAttribute for more details.
Parameters, on the other hand, can be used to get URL parameters. Your last question actually points you in the correct direction - getParameter() already returns a String so you don't need to cast it.
Properly written the line above should be:
String parameter1= request.getParameter("param1");
getParameter() - used to get url parameter from request in server side(java side).
Where as If you want to fetch any values from java side to jsp(view side)
you can use setAttribute() in Server side(Java side) and get the value using getAttribute() from jsp.
I want to get the page response (http://202.72.14.52/p2/cci/SearchHistory.aspx) but the page only allows post method. I could't get the response because I don't know what to set in the parameter name/value pairs. I have tried to insert some data in request parameter such as TextBox1=2015&TextBox2=1&TextBox3=2016&TextBox4=17&R1=v2&DropdownList1=01
Can you make a example using this web http://requestmaker.com/?
I am creating a REST service in Java ,and have a doubt with regards to params for the GET method .
I have to pass the below params in a GET request
Function
"GET" File status :
Params:
Time Range:(String)
FlowId:(String)
ID_A= or ID_B= or Both (String)
IS_ADD_A= or IS_ADD_B= or both (String)
Regex=(String)
Cookie=XXXXX
So as there are 6 params,so passing it as a query string would not be an efficient way and can't but the same in body(as it is against the HTTP GET specification)
Making this as a POST call would be against the REST principle as I want to get data from the server ,
What would be an efficient way of solving this ,would passing the params as query string is out of question,passing it in body which is against the HTTP spec ,making this as headers which may also be not good ,making this as POST request which will voilate the fielding's REST principle .
Passing data in the body of an HTTP GET call is not only against the spec but causes problems with various server-side technologies which assume you don't need access to the body in a GET call. (Some client side frameworks also have some issues with GET and a query in the body) If you have queried with long parameters I'd go with POST. It's then using POST for getting data but you'd not be the only one having to go this way to support potentially large queries.
If your parameters values aren't very long, using query string is your best option here. 6 params is not a lot, as long you don't exceed the IE limit of characters in the path - 2,048 (http://www.boutell.com/newfaq/misc/urllength.html). For example Google search engine uses many more params then 6. If there is a possibility that the URL path will exceed the limit above, you should use POST instead.
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Closed 10 years ago.
Possible Duplicate:
Servlets: doGet and doPost
I know doGet() request is appended to the request URL in a query string.But I don't know the concept of doPost() request.how does doPost request posting information to the server.
Please Guide me to get the working concept of doPost request...
Post requests are used usually for sending data to Server, and get request for reading data from server. In Post request data is sent in http request body, so data size can be very large compared to Get. If a browser fires an POST request (usually a form submit) doPost of the mapping Servlet will be called. There is another overloaded method (service()) which is called for both GET and POST
In doPost() the data is not appended in the URL.
It can handle large amount of data compared to the doGet() method.
Filling of form and submitting is done through doPost(), it's secure to use doPost() during submission of the username and password.
There is also differnce in the doGet() and doPost() header and body structure.
The main conceptual difference GET and POST is that, GET is used for getting the data from the server, and POST is used for updating the data to the server.
In general POST has the following properties:
The data is x-www-form-urlencoded . Which means, the request parameters are sent as request body. And the server has to parse the request body for parameters.
By default, when no content-length header is present, the default value for GET is 0 whereas for POST it is till end of stream.
GET is Idempotent whereas POST is Non-Idempotent. i.e, Proxies on failures for GET they retry. But, for POST they do not retry.
doGet() can be used when client request doesn't intend to change stored data.
We have already shipped a client (.NET WinForms) application which sends customer data to Java server. While most of the data sent by client are accepted at server side, some records are truncated because of the presence of & character in it, as client sends raw & and do not URL encode it, we have fixed it by using the below code:
string dataBefore="A & B";
string dataBefore = System.Web.HttpUtility.UrlEncode(dataBefore);
It is impossible for us to update all the client applications(which are already shipped) and we are thinking of a server side fix.
With the help of Fiddler, we have made sure the data has left client in full, but when server reads as below:
//in java
String dataReceied=request.getParameter("data");
it gets truncated if data contains &
Could someone help us suggesting a server side(java) fix for this? Is it possible to access the request stream in java(instead of request.getParameter())?
You can get access to the raw query string using HttpServletRequest.getQueryString() (javadoc), which:
returns a String containing the query string or null if the URL contains no query string. The value is not decoded by the container.
You can them perform manual decoding on that string, instead of using getParameter().
#Wesley's idea of using getParameterMap() may not be useful, because you don't know which order the parameters were supplied in.
I'd suggest implementing this logic as a servlet filter, to decouple the fixing of the broken parameters from your actual servlet logic. This would involve writing a custom subclass of HttpServletRequestWrapper which overrides getParameter() and manuyally decodes the query string. Your servlet would then be able to use the HttpServletrequest API as though everything was tickety boo.
It is cut off because & signifies a new URL parameter in a request like this:
google.com?query=java&page=2. Java converts all these parameters to a Map, so that's where it goes wrong.
Have you tried iterating through request.getParameterMap()? The remaining data is most likely in the name of the next parameter. If that does not work, check out the API of HTTPServletRequest to see if there is another way to get your data.
Good luck!
PS How angry are you guys at the intern that wrote & shipped that client? That sounds messed up!