XML

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!