JSP getParameter问题

Question

我有一个表单，如果定时器到达，表单将自动重定向到Servlet来更新数据库。我现在的问题是，如果javascript将窗口重定向到servlet，我的request.getParameter为空。

function verify(f,whichCase){
if(whichCase == "Submit"){
    msg = "Are you sure that you want to submit this test?";
    var i = confirm(msg)
    if(i){
        parent.window.location = "sindex.jsp"
    }
   return i;
 }
}

我这样做是因为我的jsp中有一个iframe。计时器更新问题必须使用iframe。因此，当时间到或用户单击submit时，parent.window.location可以让我刷新父窗口

<form method="POST" action="${pageContext.request.contextPath}/TestServlet" onSubmit="return verify(this,whichPressed)">

我的表单当用户点击提交按钮的时间内，它会触发验证功能，让用户确认提交。所以在我的TestServlet中，我得到了这个，因为使用javascript redirect request.getParameter("answer")这个keep会返回null。

protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
if (request.getParameter("Submit") != null) {
   String ans = request.getParameter("answer");
   Answer a = new Answer(ans, no);
   aa.CreateAnswer(an,t.getTestCode(),username);
   RequestDispatcher rd = request.getRequestDispatcher("/sindex.jsp");
   rd.forward(request, response);
  }
}

下面是time up重定向到TestServlet触发doGet方法时的计时器

if((mins == 0) && (secs == 0)) {
window.alert("Time is up. Press OK to submit the test."); // change timeout message as required
var sUrl = "TestServlet";
parent.window.location = sUrl // redirects to specified page once timer ends and ok button is pressed
} else {
  cd = setTimeout("redo()",1000);
}

Answer 1

我不确定我是否理解了这个问题，但我认为您的问题在这里：

if((mins == 0) && (secs == 0)) {
window.alert("Time is up. Press OK to submit the test."); // change timeout message as required
var sUrl = "TestServlet";
parent.window.location = sUrl // redirects to specified page once timer ends and ok button is pressed
} else {
  cd = setTimeout("redo()",1000);
}

您正在重定向到TestServlet，但您没有发送任何参数，因为您没有提交表单。尝试如下所示：

    if((mins == 0) && (secs == 0)) {
    window.alert("Time is up. Press OK to submit the test."); // change timeout message as required
    var sUrl = "TestServlet";
    //myform it's a variable pointing to your form
    myform.submit();
    } else {
      cd = setTimeout("redo()",1000);
    }

希望这能有所帮助！