您好，感谢您阅读此问题：
我将首先解释用例以及我尝试过的方法：
我有一个ArrayList，它保存Courses'data，它正在FrontServlet中创建，并存储在会话中。
我想将ArrayList转换为XML，将其显示为使用XSL转换它的HTML。
我怀疑的是：我们怎样才能将ArrayList转换为XML？
我研究过如何注释类来转换它们：https://www.mkyong.com/java/jaxb-hello-world-example/
我使用静态XML对其进行转换并显示它：Java: Implementing Transform View pattern, to convert XML to HTML with an XSL file
我读过一篇关于扩展ArrayList＆lt;＆gt;的文章。能够改变它：Why my ArrayList is not marshalled with JAXB?
我首先尝试过：
/*
* 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 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;
}
}
但是我不需要Curso类本身，我需要转换存储它们的ArrayList。
此外，我目前正在会话中存储正在创建的课程。我们怎样才能在servlet中获取会话的信息？我的意思是，我们可以从当前创建的servlet和JSP页面访问它们，但是我们如何访问servlet呢？
我问上一个问题，因为在我发现的将Java转换为XML的所有示例中，它们都显示了新实例，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。
答案 0 :(得分：1)
您可以使用xstream将对象转换为xml。 Maven依赖：
<dependency>
<groupId>xstream</groupId>
<artifactId>xstream</artifactId>
<version>1.2.2</version>
</dependency>
XMLTransformer：
public class XMLTransformer {
private XStream xstream = null;
private XMLTransformer() {
xstream = new XStream();
}
public static XMLTransformer getInstance() {
return new XMLTransformer();
}
public String toXMLString(Object object) {
return xstream.toXML(object);
}
public Object toObject(String xml) {
return (Object) xstream.fromXML(xml);
}
}
主要课程
public class Main {
public static void main(String[] args) {
XMLTransformer transformer=XMLTransformer.getInstance();
Employee e1=new Employee("gati","id");
Employee e2=new Employee("gati","id");
Employee e3=new Employee("gati","id");
List<Employee> employeeList =new ArrayList<>();
employeeList.add(e1);
employeeList.add(e2);
employeeList.add(e3);
String str=transformer.toXMLString(employeeList);
System.out.println(str);
}
}
public class Employee {
private String name;
private String email;
public Employee(String name, String email) {
this.name = name;
this.email = email;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}