servlet 请求转发

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext servletContext = this.getServletContext();
        RequestDispatcher requestDispatcher = servletContext.getRequestDispatcher("/js");//转发的请求路径
        requestDispatcher.forward(req,resp);//调用forword方法实现请求转发
    }

合为一句

   @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext servletContext = this.getServletContext();
     servletContext.getRequestDispatcher("/js").forward(req,resp);
    }

设置webapp映射

运行测试

 页面内容显示为/js页面内容 但是url路径依旧是/fs

转发，路径不变，页面变

请求转发会有可能导致数据重复提交

转发是站内请求,重定向是站外请求

重定向两次请求，转发一次请求