how to fix Cannot call sendRedirect() after the response has been committed?

Question

I am trying to pass values from servlet to jsp page using the code below:

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

    PrintWriter out = response.getWriter();
    try {
        System.out.println("try");

        String taskid=request.getParameter("id");   
        convty = new Connectivity();
        con = convty.setConnection();
        st=con.createStatement();

        query="select * from task_table";

        rset=convty.getResultSet(query, con);
        while(rset.next()) {
            System.out.println("while");
            lst.add(rset.getString("task_id"));
            lst.add(rset.getString("date"));
            lst.add(rset.getString("project_name"));    
        }
        rset.close();
        System.out.println("after while");

    } catch(Exception e) {

        RequestDispatcher dd= request.getRequestDispatcher("error.jsp");
        dd.forward(request, response);

    } finally {
        System.out.println("finally1");
        HttpSession sessionvar = request.getSession();
        sessionvar.setAttribute("TaskData", "lst");

        response.sendRedirect("usertaskpage.jsp");

        lst.clear();
        out.close();            
    }
}

when I run my page I am getting:

Error :

java.lang.IllegalStateException: Cannot call sendRedirect() after the response has been committed
    org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:483)
    src.Taskservlet.doPost(Taskservlet.java:108)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)

I tried to use:

RequestDispatcher dd=request.getRequestDispatcher("usertaskpage.jsp");
dd.forward(request, response);

but I got the same error.

How to fix this error?

score 21 · Accepted Answer · edited Mar 28 '15 at 21:38

you have already forwarded the response in catch block:

RequestDispatcher dd = request.getRequestDispatcher("error.jsp");

dd.forward(request, response);

so, you can not again call the :

response.sendRedirect("usertaskpage.jsp");

because it is already forwarded (committed).

So what you can do is: keep a string to assign where you need to forward the response.

    String page = "";
    try {

    } catch (Exception e) {
      page = "error.jsp";
    } finally {
      page = "usertaskpage.jsp";
    }

RequestDispatcher dd=request.getRequestDispatcher(page);
dd.forward(request, response);

score 4 · Answer 2 · edited Jan 12 '16 at 18:28

The root cause of IllegalStateException exception is a java servlet is attempting to write to the output stream (response) after the response has been committed.

It is always better to ensure that no content is added to the response after the forward or redirect is done to avoid IllegalStateException. It can be done by including a ‘return’ statement immediately next to the forward or redirect statement.

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score 2 · Answer 3 · answered Oct 14 '14 at 04:29

2

you can't call sendRedirect(), after you have already used forward(). So, you get that exception.

answered Oct 14 '14 at 04:29

DeepInJava

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how to fix Cannot call sendRedirect() after the response has been committed?

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