How to get parameters from the URL with JSP

EL: Raising the bar for code clarity

We all want to write less and do more. Traditional request.getParameter() feels a bit verbose, so let's consider adopting the Unified Expression Language (EL) for lighter syntax:

${param.userId} // "Can I get a userId, please?" says EL in posh English.
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Variables like param.userId are resolved at runtime, making your JSPs dynamically responsive. Special characters in a parameter's name? Fret not. EL has your back:

${param['us-erId']} // "No worries mate, I got this!" EL to the rescue.
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Important considerations for parameter retrieval

Missing parameters? Gracefully accepted.

Maintain your JSP's dignity by constantly checking for null values. Assume nothing:

String userId = request.getParameter("userId"); // yoink!
if(userId != null) {
  // "Phew, userId exists!" Relief ensues.
}
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Saving your JSP from Null Pointer Exceptions since 1998.

Using JSTL for easier readability

Let's ditch Java code in JSP. It's like pineapple on pizza, not very popular. Well, say hello to taglibs such as JSTL:

<c:if test="${not empty param.userId}">
  User ID: ${param.userId} // Like printing money, but legal.
</c:if>
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Step-by-step guide to fetching URL parameters

1. Get hold of the URL (like requesting a pizza)
2. Reach out for the right parameter (like choosing the toppings)
3. Harvest the value (the moment you take the first bite)

String value = request.getParameter("key"); // Voila, you've got the "key" to success!
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The "value" you just fetched is the meat of the URL you accessed.

Bits and pieces that matter

• When you manipulate the Param object, remember it's read-only. It won't bite you back, I promise.
• Always favor EL over scriptlets. It's like driving the car over pushing it.
• JSTL is your BFF when handling code within HTML tags.