Develop Reference

Request parameter is modified in my servlet

I sent one request as URL with data to servlet, But by default servlet is modifying the data and sending as request. Can you please suggest how to maintain the request URL with data which i passed to servlet should remain same ?
Example:- when i am passing the data to servlet
http://localhost/helloservlet/servlet/ppd.abcd.build.coupons.CouponValueFormatterServlet?dsn=frd_abc_abcde&lang=ENG&val=PRCTXT|12345 &ABCDEFG
when it using the above url in servelt as request , like string abc = request.getParameter("val"), the val attribute is trimmed automatically and assigned as " val=PRCTXT|12345" but it supposed to be like " val = PRCTXT|12345 &ABCDEFG ". Please help me on this.

The servlet interprets each & in the URL as the start of a new parameter. So when it sees &ABCDEFG, it thinks you are sending a new parameter called ABCDEFG with no value (though this is technically a "keyless value" according to the specifications).
Two things to fix this, first is when you want to actually send an &, use %26 instead. This will be skipped by the code that divides up the parameters, but converted to a real & in the parameter's value.
Second is to replace spaces with +. Spaces in URLs work sometimes but can be problematic.
So your actual request URL should look like this:
http://localhost/helloservlet/servlet/ppd.abcd.build.coupons.CouponValueFormatterServlet?dsn=frd_abc_abcde&lang=ENG&val=PRCTXT|12345+%26ABCDEFG
If you're building these parameters in javascript, you can use encodeURIComponent() to fix all problem characters for you. So you could do something like this:
var userInput = *get some input here*
var addr = 'http://www.example.com?param1=' + encodeURIComponent(userInput);

Can we display parameters sent by response.sendRedirect on the next page. If yes, how?

Is this the correct way to display parameter sent by,
response.sendRedirect("index.jsp?a="+1);
alert(<%=request.getParameter("a")%>);

response.sendRedirect("nextPage.jsp?paramName=someValue");
So on nextPage.jsp you have to write
String value = request.getParameter("paramName");
to get parameter value back.

JSP Request Parameter truncated after passing to javascript function

I have an issue with a parameter that I'm trying to pass into a Javascript function where the parameter gets cut off.
In my Servlet, I have set a parameter request.setAttribute("questions", service.getQuestions("123"))
It sets a list of questions with each question containing several values;
I loop through them with a JSTL loop <c:forEach var="data" items="${questions}">...</c:forEach> which I can then access the values as so ${data.question}, ${data.options} etc.
console.log(${data.question}) returns a value of the form 123,45,35|43,94,73|23,91,34 which is as expected.
But when I try to pass this ${data.question} into a javascript function such as <script>MyFunction(${data.question})</script>, it only receives 123.
MyFunction(data) {
console.log(data); //Only shows 123
//Split the string into arrays for processing
}

You receive first element becouse your function expect one parameter, and your value 123,45,35|43,94,73|23,91,34 is split by comma so it looks for function like diferent parametrs. Use arguments property insted or pass all value as string in '' like this
<script>MyFunction('${data.question}')</script>
Sorry for my english.. still working on it

Passing nullable parameters to a Page via PageParameters in Wicket 6

I need to pass a parameter to my page and I can't find a way to pass parameters that might be null.
If I do:
PageParameters pageParameters = new PageParameters ();
pageParameters.add ("key", null);
This will result in an exception
java.lang.IllegalArgumentException: Argument 'value' may not be null.
at org.apache.wicket.util.lang.Args.notNull(Args.java:41)
If I use Google Guava's Optional, I can't find any way to cast the object even if the the Optional object is not holding a null ie not equals to Optional.absent() :
In my landing page's constructor I do
StringValue sv = parameters.get ("key");
sv.to ( Optional.of (MyEnum.SOME_ENUM_CONSTANT).getClass () );
and when I run it I get this error:
org.apache.wicket.util.string.StringValueConversionException: Cannot
convert 'Optional.of(SOME_ENUM_CONSTANT)'to type class
com.google.common.base.Present.
Am I doing something wrong?
Is there any other way to pass a possibly null object in wicket 6?
I noticed in wicket 1.4 they have PageParameters.NULL which seems to have dissapeared in wicket 6.
Thank you

This might be too simple, but what's wrong with
Object value = ?
if (value != null) {
pageParameters.add ("key", value);
}
and
StringValue sv = pageParameters.get("key");
if (!sv.isNull()) {
// process string value
}

All page parameters in wicket will be treated as Strings eventually. The idea is that a page parameter will be on the URL of the request.
From the javadoc:
Suppose we mounted a page on /user and the following url was accessed /user/profile/bob?action=view&redirect=false. In this example profile and bob are indexed parameters with respective indexes 0 and 1. action and redirect are named parameters.
If you add something like x=y&x, the parameter x will appear twice, once with the String y and another with the empty string.
Depending on what you are trying to accomplish I would suggest to either
Don't pass the parameter at all when there is a null value required and use the isNull or toOptional methods.
Use indexed parameters and test for presence of a certain word

Java -> Apache Commons StringEscapeUtils -> escapeJavaScript

For a very simple ajax name lookup, I'm sending an id from the client webpage to the server (Tomcat 5.5, Java 5), looking it up in a database and returning a string, which is assigned to a javascript variable back in the client (and then displayed).
The javascript code that receives the value is pretty standard:
//client code - javascript
xmlHttp.onreadystatechange=function() {
if (xmlHttp.readyState==4) {
var result = xmlHttp.responseText;
alert(result);
...
}
...
}
To return the string, I originally had this in the server:
//server code - java
myString = "...";
out.write(myString.getBytes("UTF-8"));
Which worked perfectly, if unsafe. Later, I replaced it with:
import org.apache.commons.lang.StringEscapeUtils;
...
myString = "...";
out.write(StringEscapeUtils.escapeJavaScript(myString).getBytes("UTF-8"));
But while safer, the resulting string can't be properly displayed if it contains special chars like "ñ".
For instance, using:
escapeJavaScript("años").getBytes("UTF-8");
sends:
an\u00F1os
to the client.
The question: is there a simple way to parse the resulting string in Javascript or is there an alternate escape function I can use in java that would prevent this issue?

The following works in every browser I've tried:
javascript:alert("a\u00F1os");
Perhaps your string is being escaped twice by mistake.

Actually, now that I read it over, I think I actually don't need to escape the string I'm sending back at all... That is, StringEscapeUtils.escapeJavaScript would be useful if the resulting value was printed in the page, like:
//javascript code with inline struts
var myJavasriptString = "<%=myJavaString%>";
Or am I missing something and there would still be a valid reason to do the escape in the original case? (when it is returned as a series of bytes back to an ajax onreadystatechange handler and assigned to a js variable)