servlet 容器中的问题，两次获取 servlet 位置

Question

我正在学习JSP/Servet并尝试做一个简单的Servlet控制器。

这是我的项目结构：

测试是主页，用户可以输入his/her爱好。确认页面，将向用户确认详细信息。它可以选择返回并编辑信息或将信息提交到 process.jsp 页面。

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" 
id="WebApp_ID" version="4.0">
  <servlet>
    <servlet-name>FirstController</servlet-name>
    <servlet-class>ch2.servletController.Controller</servlet-class>         
  </servlet>
  <servlet-mapping>
    <servlet-name>FirstController</servlet-name>
    <url-pattern>/ch2/servletController/Controller</url-pattern>
  </servlet-mapping>
</web-app>

Test.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html lang="eu">
    <head>
        <meta charset="UTF-8">
        <title>Simple web page</title>
    </head>
    <body>
    <p>
    This is a simple HTML page that has a form in it.
        <form action="ch2/servletController/Controller">
        <p>
            Hobby:<input type="text" name="hobby" value="${param.hobby}">
            <input type="submit" name ="confirmButton" value="confirm">
        </form>

    </body>
</html>

Confirm.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Confirm Page</title>
</head>
<body>
    <p>
        The value of the hobby that was sent to this page is <strong>${param.hobby} </strong>.
    <p>
    <form action="ch2/servletController/Controller">
    <p>
        If there is any error, please click the edit button and 
            to process press the Submit button <br>
        <input type="hidden" name="hobby" value="${param.hobby}">
        <input type="submit" name="editButton" value="Edit">
        <input type="submit" name="submit" value="submit">
    </form>
</body>
</html>

Process.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="ISO-8859-1">
    <title>Process Page</title>
    </head>
    <body>
    Thank you for your information, Your hobby of <strong>${param.hobby} </strong> will
    be added to our records, eventually.
    </body>
    </html>

Controller.java

package ch2.servletController;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/Controller")
public class Controller extends HttpServlet {
    private static final long serialVersionUID = 1L;


    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {
        String address;
        if(request.getParameter("submit") != null)
        {
            address = "Process.jsp";
        }
        else if ( request.getParameter("editButton") != null)
        {
            address = "test.jsp";
        }
        else
        {
            address = "/Confirm.jsp";
        }

        RequestDispatcher dispatcher = 
                request.getRequestDispatcher(address);
        dispatcher.forward ( request, response);
    }
}

test.jsp 输出：

点击确认：

但是我无法返回 test.jsp 页面和 Process.jsp 页面：

这是我在单击 confirm.jsp 页面的编辑按钮时遇到的错误。

据我所知，我的路径不正确，甚至 servlet 位置也在重复。是否可以解释为什么 servlet 位置重复以及我如何通过控制器成功导航到 test.jsp？

非常感谢您的提前反馈。

编辑 1：

感谢 areus 的反馈。修改 confirm.jsp 上的操作后，出现以下错误。 URL 不再重复，但无法返回。

请查找 HTML 代码 confirm.jsp:

<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Confirm Page</title>
</head>
<body>
    <p>
        The value of the hobby that was sent to this page is <strong>web programming </strong>.
    <p>
    <form action="/ch2/servletController/Controller">
    <p>
        If there is any error, please click the edit button and 
            to process press the Submit button <br>
        <input type="hidden" name="hobby" value="web programming">
        <input type="submit" name="Edit" value="Edit">
        <input type="submit" name="submit" value="submit">
    </form>
</body>
</html>

Answer 1

在 Confirm.jsp 中的表格中，您使用的是亲戚 URL：ch2/servletController/Controller。 URL 是相对于为请求提供服务的资源的位置（浏览器地址栏中的位置），http://localhost:9191/SampleProject/ch/servletController/Controller.

你应该对你 Confirm.jsp 使用绝对 URL，使用：

<form action="${pageContext.request.contextPath}/ch2/servletController/Controller">

servlet 容器中的问题，两次获取 servlet 位置

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