The Java Developers Almanac 1.4


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Home > List of Packages > javax.servlet.jsp  [18 examples] > Java Server Pages Input  [4 examples]

e1053. Getting a Request Parameter in a JSP Page

In a GET request, the request parameters are taken from the query string (the data following the question mark on the URL). For example, the URL http://hostname.com?p1=v1&p2=v2 contains two request parameters - - p1 and p2. In a POST request, the request parameters are taken from both query string and the posted data which is encoded in the body of the request.

This example demonstrates how to include the value of a request parameter in the generated output:

    Hello <b><%= request.getParameter("name") %></b>!
If the page was accessed with the URL:
    http://hostname.com/mywebapp/mypage.jsp?name=John+Smith
the resulting output would be:
    Hello <b>John Smith</b>!
If name is not specified on the query string, the output would be:
    Hello <b>null</b>!
This example uses the value of a query parameter in a scriptlet:
    <%
        if (request.getParameter("name") == null) {
            out.println("Please enter your name.");
        } else {
            out.println("Hello <b>"+request.getParameter(i)+"</b>!");
        }
    %>
See also e1066 Getting a Request Parameter Using JSTL in a JSP Page.

 Related Examples
e1054. Including a File in a JSP Page
e1055. Passing Parameters to Another JSP Page
e1056. Using a Bean in a JSP Page

See also: Java Server Pages    Java Server Pages Headers    Java Server Pages Output   


© 2002 Addison-Wesley.