【发布时间】：2018-02-20 10:17:40
【问题描述】：
您好，感谢您阅读此问题：
我将首先解释用例和我尝试过的方法：
我有一个包含 Courses 数据的 ArrayList，它正在 FrontServlet 中创建并存储在会话中。
我想将 ArrayList 转换为 XML 以将其显示为使用 XSL 转换的 HTML。
我的疑问是：我们如何将 ArrayList 转换为 XML？
我研究了如何注释类来转换它们：https://www.mkyong.com/java/jaxb-hello-world-example/
我已使用静态 XML 对其进行转换并显示：Java: Implementing Transform View pattern, to convert XML to HTML with an XSL file
我读过一篇关于扩展 ArrayList 以便能够对其进行转换的好文章：Why my ArrayList is not marshalled with JAXB?
我第一次尝试：
/*
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* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package org;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
/**
*
* @author YonePC
*/
@XmlRootElement
public class Curso {
@XmlElement
public void setTitulo(String titulo) {
this.titulo = titulo;
}
@XmlElement
public void setAutor(String autor) {
this.autor = autor;
}
@XmlElement
public void setAsignatura(String asignatura) {
this.asignatura = asignatura;
}
@XmlElement
public void setDuracion(String duracion) {
this.duracion = duracion;
}
@XmlElement
public void setVideo(String video) {
this.video = video;
}
String titulo, autor, asignatura, duracion, video;
public Curso(String titulo, String autor, String asignatura, String duracion, String video) {
this.titulo = titulo;
this.autor = autor;
this.asignatura = asignatura;
this.duracion = duracion;
this.video = video;
}
public String getTitulo() {
return titulo;
}
public String getAutor() {
return autor;
}
public String getAsignatura() {
return asignatura;
}
public String getDuracion() {
return duracion;
}
public String getVideo() {
return video;
}
}
但我不需要 Curso 类本身，我需要转换存储它们的 ArrayList。
此外，我目前将正在创建的课程存储在会话中。我们如何在 servlet 中获取会话信息？我的意思是，我们可以从当前创建它的 servlet 和 JSP 页面访问它们，但是我们如何访问 servlet？
我问上一个问题是因为在我发现的所有关于将 Java 转换为 XML 的示例中，它们都展示了新实例，而不是如何转换以前存储的实例。
我试过的代码：
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package frontController;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.Curso;
/**
*
* @author YonePC
*/
@WebServlet(name = "CourseInfoCommand", urlPatterns = {"/CourseInfoCommand"})
public class CourseInfoCommand extends FrontCommand {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
public String getServletInfo() {
return "Short description";
}// </editor-fold>
@Override
public void process(HttpServletRequest request) {
try {
File file = new File("C:\\Users\\YonePC\\Videos\\ASAPLICACIONCURSOSPRACTICA1\\src\\java\\frontController\\Cursos.xml");
ArrayList courses = (ArrayList) session.getAttribute("cursos");
JAXBContext jaxbContext = JAXBContext.newInstance(ArrayListCourses.class);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
jaxbMarshaller.marshal(courses, file);
TransformerFactory factory = TransformerFactory.newInstance();
StreamSource xsl = new StreamSource(new File(""));
Transformer newTransformer = factory.newTransformer(xsl);
StreamSource xml = new StreamSource(new File(""));
PrintWriter writer = response.getWriter();
Result result = new StreamResult(writer);
newTransformer.transform(xml, result);
writer.println(writer.toString());
forward("/CourseInfo.jsp");
} catch (ServletException ex) {
Logger.getLogger(CourseInfoCommand.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(CourseInfoCommand.class.getName()).log(Level.SEVERE, null, ex);
} catch (TransformerConfigurationException ex) {
Logger.getLogger(CourseInfoCommand.class.getName()).log(Level.SEVERE, null, ex);
} catch (TransformerException ex) {
Logger.getLogger(CourseInfoCommand.class.getName()).log(Level.SEVERE, null, ex);
} catch (JAXBException ex) {
Logger.getLogger(CourseInfoCommand.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
感谢您的帮助。
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