Question

我正在学习JSP / Servet，并尝试制作一个简单的Servlet控制器。

这是我的项目结构：

test是主页，用户可以输入自己的爱好。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：

但是我无法返回到test.jsp页面和Process.jsp页面：

这是我单击confirm.jsp页面的编辑按钮时遇到的错误。

我注意到我的路径不正确，甚至servlet位置也在重复。能否解释为什么servlet位置重复，以及如何通过控制器成功导航到test.jsp？

非常感谢您的提前反馈。

Edit1：

感谢areus提供反馈。修改对Confirm.jsp的操作后，出现以下错误。 URL不再重复，但无法导航。

请为confirm.jsp找到HTML代码：

<!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中的表单上，您使用的是相对URL：ch2/servletController/Controller。 URL与服务请求的资源的位置（浏览器的地址栏中的位置）http://localhost:9191/SampleProject/ch/servletController/Controller相关。

您应该在Confirm.jsp上使用绝对网址，使用：

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

在Servlet容器中发出，两次获得Servlet位置

1 个答案: