java - 空指针异常 requestDispatcher

Question

String fn=request.getParameter("fn");
request.setAttribute("eno",eno);
RequestDispatcher rd = request.getRequestDispatcher("../WebRoot/displayperson.jsp");

rd.forward(request, response);

它不会调用jsp的

Answer 1

ServletRequest#getRequestDispatcher(String) 的 javadoc州

a RequestDispatcher object that acts as a wrapper for the resource at the specified path, or null if the servlet container cannot return a RequestDispatcher

您提供的路径似乎不存在或无法按照您期望的方式解析。