getParameter

GetParameter is a method name used in several programming contexts to retrieve the value associated with a named parameter from a data source, such as an HTTP request or an application configuration. It is commonly used to access user input, query string data, or configuration values in a consistent way across different components or frameworks.

In the Java Servlet API, HttpServletRequest.getParameter(String name) returns the value of the request parameter as a String. This parameter can originate from the query string in a GET request or from form data in a POST request. If multiple values exist for the same parameter name, getParameter returns the first value, while getParameterValues(String name) can be used to obtain all values. A map of all parameters can be retrieved with getParameterMap.

Historically, Java Applets also provided a getParameter(String name) method, which reads values supplied in the HTML page via <param> elements attached to the applet. This usage is now largely deprecated as applets have fallen out of favor on the web.

Across different frameworks and languages, getParameter-like methods share a common behavior: they return the parameter value as a string or null if the parameter is not present. Returned values are typically untrusted and may require validation or sanitization to prevent security issues such as injection attacks. Developers should also be aware of how empty values are handled, which can vary by implementation.

See also: getParameterValues, getParameterMap, parameter retrieval patterns in web frameworks.