Using Query String Parameters in a Visualforce Page

To access query string parameter value in custom controller
String value = ApexPages.currentPage().getParameters().get(‘name’);

To access query string parameter value in visual force page
{!$CurrentPage.parameters.name}

To setting param value
ApexPages.currentPage().setParameters().put(‘name’, ‘sandeep’);

The setParameters() method is only valid inside test methods.