Question

我有一个小应用程序（HTML表单，servlet作为控制器和jsp文件），我试图弄清楚为什么我不能将请求从servlet转发到jsp文件。

问题是从html提交后，显示“HTTP Status 404”

申请流程：

从html提交。
controller从html获取名称。
控制器应该将请求移动到jsp文件。

谢谢！

项目层次结构： http://s23.postimg.org/kgt7r7lwb/Capture.jpg

main.html中：

<html>
<title>Coupons categories</title>
<body>
  <h1 align="center">Coupons categories</h1>
  <form method="GET" action="Controller">
    Select category 
    Type:
    <select name="type" size=1>
      <option value="restaurants">Restaurants</option>
      <option value="electrics">Electrics</option>
      <option value="hotels">Hotels</option>
    </select>
    <br><br>
      <input type="Submit">
   </form>
</body>
<html>

controller.java：

   @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //PrintWriter out = response.getWriter();
        //out.write(request.getPathInfo());

        String path = request.getParameter("type");
        if(path.equals("electrics"))
        {
            request.setAttribute("timestamp", new Date());
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/view/electrics.jsp");
            dispatcher.forward(request, response);
        }
        else if(path.equals("hotels"))
        {
            request.setAttribute("timestamp", new Date());
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/view/hotels.jsp");
            dispatcher.forward(request, response);          
        }
        else if(path.equals("restaurants"))
        {
            request.setAttribute("timestamp", new Date());
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/view/restaurants.jsp");
            dispatcher.forward(request, response);          
        }
    }

electrics.jsp：

<%@ page language="java" contentType="text/html; charset=windows-1255"
    pageEncoding="windows-1255"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1255">
<title>Insert title here</title>
</head>
<body>
    <h2>products list...</h2>
    <%
    Object ob = request.getAttribute("timestamp");
    out.println(ob);
    %>
</body>
</html>

的web.xml：

    <description>
      CouponsServer
    </description>
    <display-name>Controller for CouponsServer</display-name>

    <servlet>
      <servlet-name>Controller</servlet-name>
      <servlet-class>uses.server.Controller</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Controller</servlet-name>
        <url-pattern>/Controller</url-pattern>
    </servlet-mapping>


</web-app>

更新：可能问题出在controller.java中。当我尝试以下代码时，我得到HTTP状态500。 protected void doGet（HttpServletRequest request，HttpServletResponse response）抛出ServletException，IOException {

        PrintWriter out = response.getWriter();
        out.write(request.getPathInfo());
    }

Answer 1

试试这个

 request.getRequestDispatcher("/view/electrics.jsp").forward(req,res);

Answer 2

的web.xml

<servlet>
    <servlet-name>Controller</servlet-name>
    <servlet-class>uses.server.Controller</servlet-class>
</servlet>

<servlet-mapping>
     <servlet-name>Controller</servlet-name>
     <url-pattern>/Controller</url-pattern>
</servlet-mapping>

<welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

Answer 3

您的代码在我的本地运行正常，最后使用欢迎列表定义了web.xml，甚至没有它。尝试使用动态Web内容版本2.5运行的代码，其中自动生成web.xml。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
 <description>
      CouponsServer
    </description>
  <display-name>Controller for CouponsServer</display-name>


  <servlet>

    <display-name>Controller</display-name>
    <servlet-name>Controller</servlet-name>
    <servlet-class>uses.server.Controller</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Controller</servlet-name>
    <url-pattern>/Controller</url-pattern>
  </servlet-mapping>
</web-app>

从servlet转发到jsp的请求

3 个答案: