(Quick Reference)
params
Purpose
A mutable multi-dimensional map (hash) of request (CGI) parameters.
Examples
To obtain a request parameter called
id:
class BookController {
def show() {
def book = Book.get(params.id)
}
}To perform data binding (see
Data Binding in the user guide):
def save() {
def book = new Book(params) // bind request parameters onto properties of book
}Description
The standard Servlet API provides access to parameters with the
HttpServletRequest object. Although Grails provides the same capability through the
request object, it goes a bit further by providing a mutable map of request parameters called
params.
The
params object can be indexed into using the array index operator or de-reference operator, so given the URL
/hello?foo=bar you can access
foo with
println params.foo
The params object can also be used to bind request parameters onto the properties of a domain class using either the constructor or the
properties property:
def book = new Book(params)
book = Book.get(1)
book.properties = params
For further reading see
Data Binding in the user guide.
