Pass Hidden parameters using response sendRedirect

Question

How would I pass hidden parameters  I want to call a page  test jsp  but also pass 2 hidden parameters like a post   response sendRedirect   content test jsp

User · Answer

Using session  I successfully passed a parameter  name  from servlet  1 to servlet  2  using response sendRedirect in servlet  1  Servlet  1 code   protected void doPost HttpServletRequest request  HttpServletResponse response        String name   request getParameter  name        String password   request getParameter  password                request getSession   setAttribute  name   name       response sendRedirect   todo do      In Servlet  2  you don t need to get name back  It s already connected to the session  You could do String name    String  request getSession   getAttribute  name    ---but you don t need this   If Servlet  2 calls a JSP  you can show name this way on the JSP webpage    lt h1 gt Welcome   name  lt  h1 gt

User · Answer

To send a variable value through URL in response sendRedirect    I have used it for one variable  you can also use it for two variable by proper concatenation   String value  xyz    response sendRedirect   content test jsp var   value

User · Answer

Generally  you cannot send a POST request using sendRedirect   method  You can use RequestDispatcher to forward   requests with parameters within the same web application  same context   RequestDispatcher dispatcher   servletContext   getRequestDispatcher  test jsp    dispatcher forward request  response     The HTTP spec states that all redirects must be in the form of a GET  or HEAD    You can consider encrypting your query string parameters if security is an issue   Another way is you can POST to the target by having a hidden form with method POST and submitting it with javascript when the page is loaded

User · Answer

TheNewIdiot s answer successfully explains the problem and the reason why you can t send attributes in request through a redirect  Possible solutions    Using forwarding  This will enable that request attributes could be passed to the view and you can use them in form of ServletRequest getAttribute or by using Expression Language and JSTL  Short example  reusing TheNewIdiot s answer  code    Controller  your servlet   request setAttribute  message    Hello world    RequestDispatcher dispatcher   servletContext   getRequestDispatcher url   dispatcher forward request  response     View  your JSP   Using scriptlets    lt       out println request getAttribute  message       gt    This is just for information purposes  Scriptlets usage must be avoided  How to avoid Java code in JSP files   Below there is the example using EL and JSTL    lt c out value    message     gt   If you can t use forwarding  because you don t like it or you don t feel it that way or because you must use a redirect  then an option would be saving a message as a session attribute  then redirect to your view  recover the session attribute in your view and remove it from session  Remember to always have your user session with only relevant data  Code example  Controller    if request is not from HttpServletRequest  you should do a typecast before HttpSession session   request getSession false     save message in session session setAttribute  helloWorld    Hello world    response sendRedirect   content test jsp      View  Again  showing this using scriptlets and then EL   JSTL    lt       out println session getAttribute  message         session removeAttribute  message      gt    lt c out value    sessionScope message     gt   lt c remove var  message  scope  session    gt

[java] Pass Hidden parameters using response.sendRedirect()

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