This document discusses how to work with XML files in Java. It provides examples of using JAXB to generate XML files from Java objects and parse XML files into Java objects. Code samples are given to demonstrate how to: 1) Create a Java class to represent an employee object and annotate it for XML conversion 2) Write a program that takes an employee object and generates an XML file 3) Create Java classes to represent objects in an XML file containing a list of horses and their attributes 4) Use JAXB to export a list of horse objects to an XML file and import an XML file back into a list of horse objects.

1. WORK WITH XML-files in
Java
Для студентов
старших курсов университетов
Ст.преподаватель Дудник О.А.

2. • XML-eXtensible Markup
Language(расширяемыXй язык
разметок)

3. • XML-файлы можно использовать в
.качестве базы данных
• Для чтения и записи в такие файлы в
Java используется библиотека JAXB.
• Для ее подключения нужно дописать
• import
javax.xml.bind.annotation.XmlAccessType;
import
javax.xml.bind.annotation.XmlAccessorType;
import
javax.xml.bind.annotation.XmlRootElement;

4. • File: employee.xml
• <?xml version="1.0" encoding="UTF-
8" standalone="yes"?>
• <employee id="1">
• <name>Vimal Jaiswal</name>
• <salary>50000.0</salary>
• </employee>

5. • Как сгенерировать этот файл?
• File: ObjectToXml.java
• import java.io.FileOutputStream;
•
• import javax.xml.bind.JAXBContext;
• import javax.xml.bind.Marshaller;
•
•
• public class ObjectToXml {
• public static void main(String[] args) throws Exception{
• JAXBContext contextObj = JAXBContext.newInstance(Employee.class);
•
• Marshaller marshallerObj = contextObj.createMarshaller();
• marshallerObj.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
•
• Employee emp1=new Employee(1,"Vimal Jaiswal",50000);
•
• marshallerObj.marshal(emp1, new FileOutputStream("employee.xml"));
•
• }
• }

6. • File: Employee.java
• import javax.xml.bind.annotation.XmlAttribute;
• import javax.xml.bind.annotation.XmlElement;
• import javax.xml.bind.annotation.XmlRootElement;
•
• @XmlRootElement
• public class Employee {
• private int id;
• private String name;
• private float salary;
•
• public Employee() {}
• public Employee(int id, String name, float salary) {
• super();
• this.id = id;
• this.name = name;
• this.salary = salary;
• }
• @XmlAttribute
• public int getId() {
• return id;
• }
• public void setId(int id) {
• this.id = id;
• }
• @XmlElement
• public String getName() {
• return name;
• }
• public void setName(String name) {
• this.name = name;

7. • Рассмотрим еще пример XML-файла:
• <?xml version="1.0" encoding="UTF-8"
standalone="yes"?>
<horseList>
<horse>
<horse_number>1</horse_number>
<name_horse>That Darn Gray Cat</name_horse>
<odds>5</odds>
<did_win>lost</did_win>
</horse>
<horse>
<horse_number>2</horse_number>
<name_horse>Fort Utopia</name_horse>
<odds>10</odds>
<did_win>win</did_win>
</horse>
• </horseList>

8. • @XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement( name ="horse" )
• public class Horse {
public String horse_number;
public String name_horse;
public String odds;
public String did_win;
public void setHorse_number(String horse_number) {
this.horse_number = horse_number;
}
public void setName_horse(String name_horse) {
this.name_horse = name_horse;
}
public void setOdds(String odds) {
this.odds = odds;
}
public void setDid_win(String did_win) {
this.did_win = did_win;
}
public String getHorse_number() {
return horse_number;
}
public String getName_horse() {
return name_horse;
}
public String getOdds() {
return odds;

9. • @XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement( name ="horseList" )
public class HorseList {
@XmlElement( name = "horse", type =Horse.class )
private List<Horse> horseList =new ArrayList<Horse>();
public HorseList(){}
public HorseList(List<Horse> horseList){
this.horseList = horseList;
}
public List<Horse> getHorseList() {
return horseList;
}
public void setHorseList(List<Horse> horseList) {
this.horseList = horseList;
}
// Export
public static void marshal(List<Horse> ids, File selectedFile)
throws IOException, JAXBException {
JAXBContext context;
BufferedWriter writer = null;
writer = new BufferedWriter(new FileWriter(selectedFile));
context = JAXBContext.newInstance(HorseList.class);
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
m.marshal(new HorseList(ids), writer);
writer.close();
}
// Import
public static List<Horse> unmarshal(File importFile) throws

11. • УСПЕХОВ!