getParameterMap

getParameterMap is a method in the Java Servlet API, defined on HttpServletRequest. It returns a map that relates parameter names to their values as arrays of strings. The method signature is Map<String, String[]> getParameterMap(). The map contains each parameter name as a key and a String[] of its values as the corresponding value. If a parameter appears multiple times in the request, all of its values are present in the array for that parameter.

Parameters in the map come from both the query string and the request body for applicable POST requests (such as forms with content type application/x-www-form-urlencoded or multipart/form-data). The container typically provides values as strings and may decode them according to the request’s character encoding.

Usage of getParameterMap is common when you need to inspect or iterate over all parameters, for example to log them or pass them through to another component. For access to a single value, use getParameter, which returns the first value for a given name (or null if absent). For all values of a specific parameter, use getParameterValues to obtain the String[].

Notes: the map is intended for read-only use; mutating the map or its contents is not generally supported and may be unsupported by some implementations. If you need to modify parameter data, copy the relevant values into a separate data structure.

See also: HttpServletRequest.getParameter, HttpServletRequest.getParameterValues, HttpServletRequest.getParameterNames.