Core Servlets and JavaServer Pages™

3.1. The Role of Form Data

If you've ever used a search engine, visited an on-line bookstore, tracked stocks on the Web, or asked a Web-based site for quotes on plane tickets, you've probably seen funny-looking URLs like http://host/path?user=Marty+Hall&origin=bwi&dest=lax. The part after the question mark (i.e., user=Marty+Hall&origin= bwi&dest=lax) is known as form data (or query data) and is the most common way to get information from a Web page to a server-side program. Form data can be attached to the end of the URL after a question mark (as above), for GET requests, or sent to the server on a separate line, for POST requests. If you're not familiar with HTML forms, Chapter 16 (Using HTML Forms) gives details on how to build forms that collect ...