These 2 articles talk about how to properly prevent idempotent data from being manipulated (deleted, saved etc) more than once.
http://www.javaranch.com/journal/200603/frontman.html http://www.theserverside.com/tt/articles/article.tss?l=RedirectAfterPost I tested this on Tomcat 6.0.x, and found that regardless of which method was used (GET or POST) , if an HTTP Forward (which returns status code 200) was performed then the forms data was being saved twice. package test68.servlet; import javax.servlet.http.*; import javax.servlet.*; import java.io.IOException; public class TestPostGetServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String testInputField = request.getParameter("testInputField"); System.out.println("testInputField: " + testInputField); //rd.forward is HTTP Forward sends a 200ok status and retains the original Http Request data. //In this case when the Refresh button is pressed on the original JSP page, the form's data gets //RePOSTed //RequestDispatcher rd = getServletContext().getRequestDispatcher("/p/test68/formMethodPost.jsp"); //rd.forward(request,response); //response.sendRedirect is HTTP Redirect sends a 302 Temporarily Moved status and does not retain //the original Http Request data. In this case when the Refresh button is pressed on the original //JSP page, the form's data doesn't get RePOSTed response.sendRedirect("/p/test68/formMethodPost.jsp"); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String testInputField = request.getParameter("testInputField"); System.out.println("testInputField: " + testInputField); //HTTP Forward and HTTP Redirect , behave in a similar manner to doPost above. //RequestDispatcher rd = getServletContext().getRequestDispatcher("/p/test68/formMethodGet.jsp"); //rd.forward(request,response); response.sendRedirect("/p/test68/formMethodGet.jsp"); } } -Rashmi --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
