Form processing with Servlets

1
Form processing with Servlets

• GET method ? process form data inside doGet
  method
• POST method ? process form data inside doPost
  method
• The doPost method takes the same parameters as
  the doGet method

2
Servlet doPost method

• The doPost method header is
• public void doPost( HttpServletRequest request,
• HttpServletResponse response)
• throws IOException,
• 
  ServletException
• ? We have access to the HttpServletRequest and
  HttpServletResponse parameters (remember the 2
  implicit objects request and response in JSPs)

3
doGet and doPost methods

• One method can call the other in order to do the
  processing
• // Code the doGet method
• public void doPost( HttpServletRequest request,
• HttpServletResponse response)
• throws IOException,
• 
  ServletException
• doGet( request, response )

4
Form processing with Servlets

• To process a form, the doGet (or doPost) argument
  request can call the following methods (just like
  the implicit object request calls them in a JSP)
• getQueryString( )
• getParameter( String )
• getCookies( )
• getSession( )
• getAttribute( String )
• getAttributeNames( )

5
Form processing with Servlets

• Place form.html in webapps directory
• ltform action "go" method "POST"gt
• go should map to processForm in web.xml
• processForm.class should be in a package inside
  the WEB-INF/classes directory

6
Form processing with Servlets

• In web.xml
• ltservletgt
• ltservlet-namegtprocessFormlt/servlet-namegt
• ltservlet-classgtmypackage.processFormlt/servlet-c
  lassgt
• lt/servletgt
• ltservlet-mappinggt
• ltservlet-namegtprocessFormlt/servlet-namegt
• lturl-patterngt/golt/url-patterngt
• lt/servlet-mappinggt