从Java Bean获取数据以显示在JSP页面上 [英] Getting data from the Java bean to be displayed on a JSP page
问题描述
我有一个论坛，用户可以在其中注册详细信息，然后将其发送到Servlet，然后发送给Java Bean.我遇到的麻烦是，当请求Java bean时，我无法使数据显示在另一个JSP页面上.因此CreateAccount.jsp允许用户输入论坛.
I've got a forum where a user can register there details and this gets sent to a Servlet and then a Java bean. What I'm having trouble with is that I can't get the data to be displayed on another JSP page when the Java bean is requested. So CreateAccount.jsp allows the user to input into the forum.
该论坛已发布到Servlet(RegisterDetails.java)并将其发送到Java Bean(Register.java).然后error.jsp显示来自bean的数据.下面是我的代码.当前代码将每个值显示为null.
The forum is posted to a Servlet(RegisterDetails.java) and sends it to a Java bean (Register.java). Then error.jsp shows this data from the bean. Below is my code. The current code shows each value as null.
Register.java:
package com.cassandra.MrBlabber.servlets;
import java.io.IOException;
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("/Register")
public class Register extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Register() {
super();
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
RegisterDetails details = new RegisterDetails();
details.setName(request.getParameter("FullName"));
details.setEmail(request.getParameter("EmailAddress"));
details.setPassword(request.getParameter("Password"));
details.setUsername(request.getParameter("Username"));
request.setAttribute("details", details);
getServletContext().getRequestDispatcher("/WEB-INF/Error.jsp").forward(request, response);
}
}
RegisterDetails.java:
package com.cassandra.MrBlabber.servlets;
public class RegisterDetails {
private String fullName;
private String emailAddress;
private String password;
private String username;
public RegisterDetails() {}
public String getName() { return fullName; }
public String getEmailAddress() { return emailAddress; }
public String getPassword() { return password; }
public String getUsername() { return username; }
public void setName(String value) { this.fullName = value; }
public void setEmail(String value) { this.emailAddress = value; }
public void setPassword(String value) { this.password = value; }
public void setUsername(String value) { this.username = value; }
}
CreateAccount.jsp:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<link rel="stylesheet" type="text/css" href="/MrBlabber/css/stylesheet.css"/>
<title>MrBlabber/Create an Account</title>
</head>
<body>
<!-- Section -->
<section>
<!-- Sign Up -->
<article>
<div id="articleWrapper">
<h3>No Account? Sign Up</h3>
<form id="createAccount" onsubmit="return validateForm();" action="Register" name="createAccount" method="POST">
<input type="text" id="name" name="FullName" placeholder="Full Name"/>
<input type="text" id="email" name="EmailAddress" placeholder="Email Address"/>
<input type="password" id="password" name="Password" placeholder="Create a password"/>
<input type="text" id="username" name="Username" placeholder="Choose your username"/>
<input type="submit" value="Sign up for MrBlabber"/>
</form>
</div>
</article>
<article>
<div id="errorMessage" class="errorMessage">
<script src="/MrBlabber/javascript/CreateAccountValidation.js" type="text/javascript"></script>
</div>
</article>
</section>
</body>
</html>
Error.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="com.cassandra.MrBlabber.servlets.RegisterDetails" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>shit</h1>
<jsp:useBean id="RegisterDetails" class="com.cassandra.MrBlabber.servlets.RegisterDetails" scope="session"/>
<jsp:setProperty name="RegisterDetails" property="*"/>
<h1>
Name: <%=RegisterDetails.getName()%><br>
Email: <%=RegisterDetails.getEmailAddress()%><br>
Password: <%=RegisterDetails.getPassword()%><br>
Username: <%=RegisterDetails.getUsername()%><br>
</h1>
</body>
</html>
推荐答案
首先，您的类RegisterDetails不是bean，因为它没有实现java.io.Serializable接口.
First of all, your class RegisterDetails is not a bean because it does not implement the java.io.Serializable interface.
其次，您确实需要对来自请求的数据进行某种类型的输入清理(以防止SQL/HTML/跨站点脚本注入)，如果您要使用bean，我想应该把它放在在bean类中.
Secondly, you really need to implement some kind of input sanitization for the data coming from the request (to prevent SQL/HTML/Cross-site scripting injections), and if you are going to use beans I guess you should put that inside the bean class.
第三，您也可以省去bean的概念(这意味着您不需要jsp:useBean)，只需将RegisterDetails类的实例作为常规类对象保存到会话中，然后就可以将其从在任何页面上的会话，如下所示:
Third, you could also dispense with the bean concept (meaning you won't need jsp:useBean) and just save the instance of the class RegisterDetails as a regular class object into the session, and then you can pull it from the session on any page as follows:
在servlet中:
session.setAttribute("details", details); //saving your object to the session
在任何其他页面中:
RegisterDetails details = (RegisterDetails)session.getAttribute("details");
这篇关于从Java Bean获取数据以显示在JSP页面上的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
