Javascript JSP中用Servlet改变页面

我正在写一个JSP页面，用户可以通过单选按钮选择一个选项 按下submit后，该值将传递给servlet，servlet将检查该值并更改到特定页面， 代码如下： JSP

奇怪的是，页面一直切换到同一页面（正确的意思是

temp

没有正确的值），但我检查了参数，它工作正常（它显示dog或rabbit）

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为什么页面没有更改？

这是因为您使用了

==

来比较字符串值

因此，请始终使用

equals（）

来比较字符串值，而不是

=

阅读更多：

试试这个

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     String forward="";
     String temp = request.getParameter("dorr");
     if (temp.equals("dog")){
        forward = DOG_JSP;
     } else if (temp.equals("rabbit")){
        forward = RABBIT_JSP;
     } else {
       forward = MAIN_JSP;
     }
    RequestDispatcher view = request.getRequestDispatcher(forward);
    view.forward(request, response);  
}

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此链接可能会回答您的问题：@BalusC:谢谢您的语法编辑。

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String forward="";
String temp = request.getParameter("dorr");
if (temp=="dog"){
forward = DOG_JSP;
} else if (temp=="rabbit"){
forward = RABBIT_JSP;
} else forward = MAIN_JSP;
RequestDispatcher view = request.getRequestDispatcher(forward);
view.forward(request, response);  }

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     String forward="";
     String temp = request.getParameter("dorr");
     if (temp.equals("dog")){
        forward = DOG_JSP;
     } else if (temp.equals("rabbit")){
        forward = RABBIT_JSP;
     } else {
       forward = MAIN_JSP;
     }
    RequestDispatcher view = request.getRequestDispatcher(forward);
    view.forward(request, response);  
}