从Java Bean获取数据以显示在JSP页面上

一尘不染

从Java Bean获取数据以显示在JSP页面上

jsp

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，无法将数据显示在另一个JSP页面上。因此CreateAccount.jsp允许用户输入论坛。

该论坛被发布到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。

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>

阅读 282

2020-06-10

共1个答案

一尘不染

首先，您的类RegisterDetails不是bean，因为它没有实现java.io.Serializable接口。

其次，您确实需要对来自请求的数据实施某种输入清理（以防止SQL / HTML
/跨站点脚本注入），并且，如果您要使用Bean，我想您应该将其放在Bean中类。

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，然后可以在任何会话中将其从会话中拉出。页面如下：

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");

2020-06-10