Comments on: IllegalStateException while using JSP http://iderror.com/errors/java/java-jsp/illegalstateexception-while-using-jsp/ You have errors, we have solutions! Fri, 10 Jun 2011 15:06:54 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: adminhttp://iderror.com/errors/java/java-jsp/illegalstateexception-while-using-jsp/comment-page-1/#comment-7955 admin Fri, 20 Mar 2009 10:28:59 +0000 http://localhost/idError/?p=8027#comment-7955 a. For servlets, the easiest way to avoid this is to branch the code in your service method in such a way as to insure that calls to HttpServletResponse.sendRedirect or RequestDispatcher.forward are always the last call made before the end of the method. This can be achieved by adding a return call just after either of these.Example:public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{if("client".equals(request.getParameter("user_type"))){ response.sendRedirect("client-screen.jsp"); return; // <------- This return statement prevents any further writing to the outputStream } // // Other code that may write to the outputStream.... // }b. It is impossible to redirect from within the middle of a JSP page. Check this and correct the code. c. The simple solution to this problem is to always us a servlet for streaming binary data. a. For servlets, the easiest way to avoid this is to branch the code in your service method in such a way as to insure that calls to HttpServletResponse.sendRedirect or RequestDispatcher.forward are always the last call made before the end of the method. This can be achieved by adding a return call just after either of these.

Example:

public void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException{

if(“client”.equals(request.getParameter(“user_type”))){
response.sendRedirect(“client-screen.jsp”);
return; // <——- This return statement prevents any further writing to the outputStream
}
//
// Other code that may write to the outputStream….
//
}

b. It is impossible to redirect from within the middle of a JSP page. Check this and correct the code.
c. The simple solution to this problem is to always us a servlet for streaming binary data.

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