Question

我目前正在使用教程（http://www.java-programming.info/tutorial/pdf/csajsp2/07-Cookies.pdf）尝试启用cookie创建，我的servlet在下面的代码中有特色，但是我想添加一个href或按钮，以便在用户受到欢迎时可以点击并将其带到我的webContent文件夹中的jsp，我正在使用jsp，eclipse indigo和tomcat 6，任何提示都会有所帮助，因为添加如下所示的href无法正常工作，顺便说一下w3schools链接中的代码可以忽略不计

package The_Quiz;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

/** Servlet that processes a registration form containing
 *  a user's first name, last name, and email address.
 *  If all the values are present, the servlet displays the
 *  values. If any of the values are missing, the input
 *  form is redisplayed. Either way, the values are put
 *  into cookies so that the input form can use the
 *  previous values.
 *  <p>
 *  From <a href="http://courses.coreservlets.com/Course-Materials/">the
 *  coreservlets.com tutorials on servlets, JSP, Struts, JSF, Ajax, GWT, and Java</a>.
 */

 public class RegistrationServlet extends HttpServlet {
  @Override
  public void doGet(HttpServletRequest request,
                HttpServletResponse response)
  throws ServletException, IOException {
 response.setContentType("text/html");
 boolean isMissingValue = false;
 String firstName = request.getParameter("firstName");
 if (isMissing(firstName)) {
  firstName = "Missing first name";
  isMissingValue = true;
 }
 String lastName = request.getParameter("lastName");
    if (isMissing(lastName)) {
  lastName = "Missing last name";
  isMissingValue = true;
 }
 String emailAddress = request.getParameter("emailAddress");
 if (isMissing(emailAddress)) {
  emailAddress = "Missing email address";
  isMissingValue = true;
 }
 Cookie c1 = new LongLivedCookie("firstName", firstName);
 response.addCookie(c1);
 String formAddress =
  "The_Quiz.RegistrationForm";
       if (isMissingValue) {
  response.sendRedirect(formAddress);
    } else {
  PrintWriter out = response.getWriter();
  String docType =
    "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
    "Transitional//EN\">\n";
  String title = "Thanks for Registering";
  out.println
    (docType +
     "<HTML>\n" +
     "<HEAD><TITLE>" + title + "</TITLE></HEAD>\n" +
     "<BODY BGCOLOR=\"#FDF5E6\">\n" +
     "<CENTER>\n" +
     "<H1 ALIGN>" + title + "</H1>\n" +
     "<UL>\n" +
     "  <LI><B>First Name</B>: " +
            firstName + "\n" +
     "</UL>\n" +
     "<a href="Question_1.jsp">Visit W3Schools</a>" +       
     "</CENTER></BODY></HTML>");
     }
   }

  /** Determines if value is null or empty. */

  private boolean isMissing(String param) {
   return((param == null) ||
       (param.trim().equals("")));
        }
        }

Answer 1

您添加了Cookie，但是您获得了一个请求参数。您应该根据书中的示例创建CookieUtilities并使用CookieUtilities.getCookieValue 如果您想获得参数 - 您需要在URL中发送请求参数

Answer 2

cookie的创建应该是这样的

Cookie c = new Cookie('cookiename','value');

formAddress的第二件事你应该像这样指定url

/RegistrationForm

不要给包名。

是的，对于锚标记在单引号中指定jsp的url

内部servlet中的Ahref

2 个答案: