Руководство Java Architecture for XML Binding (JAXB)

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1- Введение

JAXB интегрирован в JDK начиная с версии 6.0. Если вы используете предыдущие версии Java вам нужно скачать и добавить в библиотеку для использования.
Статья основана на Java6, поэтому вы можете сразу начать работу без добавления библиотек.
Model of example:
Картина после выполнения project.

2- Создать project

Создать стандартный Project java.
Employee.java
package org.o7planning.tutorial.jaxb.model;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class Employee {

    private String empNo;
    private String empName;
    private String managerNo;

    /**
     * This default constructor is required if there are other constructors.
     */
    public Employee() {

    }

    public Employee(String empNo, String empName, String managerNo) {
        this.empNo = empNo;
        this.empName = empName;
        this.managerNo = managerNo;
    }

    public String getEmpNo() {
        return empNo;
    }

    public void setEmpNo(String empNo) {
        this.empNo = empNo;
    }

    public String getEmpName() {
        return empName;
    }

    public void setEmpName(String empName) {
        this.empName = empName;
    }

    public String getManagerNo() {
        return managerNo;
    }

    public void setManager(String managerNo) {
        this.managerNo = managerNo;
    }

}
 
Department.java
package org.o7planning.tutorial.jaxb.model;

import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(namespace = "http://o7planning.org/jaxb")
@XmlAccessorType(XmlAccessType.FIELD)
public class Department {

  private String deptNo;
  private String deptName;
  private String location;

  @XmlElementWrapper(name = "employees")
  @XmlElement(name = "employee")
  private List<Employee> employees;

  /**
   * This default constructor is required if there are other constructors.
   */
  public Department() {

  }

  public Department(String deptNo, String deptName, String location) {
      this.deptNo = deptNo;
      this.deptName = deptName;
  }

  public String getDeptNo() {
      return deptNo;
  }

  public void setDeptNo(String deptNo) {
      this.deptNo = deptNo;
  }

  public String getDeptName() {
      return deptName;
  }

  public void setDeptName(String deptName) {
      this.deptName = deptName;
  }

  public String getLocation() {
      return location;
  }

  public void setLocation(String location) {
      this.location = location;
  }

  public List<Employee> getEmployees() {
      return employees;
  }

  public void setEmployees(List<Employee> employees) {
      this.employees = employees;
  }

}
TestExample.java
package org.o7planning.tutorial.jaxb.test;

import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.o7planning.tutorial.jaxb.model.Department;
import org.o7planning.tutorial.jaxb.model.Employee;

public class TestExample {

    private static final String XML_FILE = "dept-info.xml";

    public static void main(String[] args) {

        Employee emp1 = new Employee("E01", "Tom", null);
        Employee emp2 = new Employee("E02", "Mary", "E01");
        Employee emp3 = new Employee("E03", "John", null);

        List<Employee> list = new ArrayList<Employee>();
        list.add(emp1);
        list.add(emp2);
        list.add(emp3);

        Department dept = new Department("D01", "ACCOUNTING", "NEW YORK");
        //
        dept.setEmployees(list);

        try {
            // create JAXB context and instantiate marshaller
            JAXBContext context = JAXBContext.newInstance(Department.class);

            // (1) Marshaller : Java Object to XML content.
            Marshaller m = context.createMarshaller();
            m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

            // Write to System.out
            m.marshal(dept, System.out);

            // Write to File
            File outFile = new File(XML_FILE);
            m.marshal(dept, outFile);

            System.err.println("Write to file: " + outFile.getAbsolutePath());

            // (2) Unmarshaller : Read XML content to Java Object.
            Unmarshaller um = context.createUnmarshaller();

            // XML file create before.
            Department deptFromFile = (Department) um.unmarshal(new FileReader(
                    XML_FILE));
            List<Employee> emps = deptFromFile.getEmployees();
            for (Employee emp : emps) {
                System.out.println("Employee: " + emp.getEmpName());
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 
Результат запуска класса  TestExample.:
Картина показывает как работает  JAXB:

3- Установки и результаты

Далее, мы поменяем некоторые настройки  Annotation, и посмотрим на результат в данной ситуации.

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