Hi everyone ! Through this post we’re going to see how to export an ArrayList of a POJO Object to an XML file.

We have a group of employees in a random company, and we want to save their data in an XML generated file as a backup using a Java Application. Each employee has these fallowing attributes

  • Code : a String text that identify each employee in the company
  • First name : the first name of the employee
  • Last name: the last name of the employee
  • Email: the email address of the employee

The logical process is very simple. First, we enumerate the employees we want to export then we write them to a List. Then, we use the same list to export the details of each employee.

We are going to create a new Java project list2xml that export an ArrayList of an Employees to an XML file. First we’ll create these following packages:

–  list2xml : root package

– list2xml.model : contains POJO classes

– list2xml.dao : contains Init method of an Employee ArrayList

– list2xml.exporter : contains one class with one method for XML exporting

– list2xml.main: contains one class Main with a main method.

Follow these steps below to create the project:

  • Under your IDE, create a new Java Project : “list2xml”
  • Add a new package : “list2xml”.
  • Under the root package, add a new one : model
  • Create a new Java class : Employee
package list2xml.model;

import java.io.Serializable;

public class Employee implements Serializable {
private String Code;
private String FirstName;
private String LastName;
private String Email;

public Employee() {}

public Employee(String Code, String FirstName, String LastName, String Email) {
this.Code=Code;
this.FirstName=FirstName;
this.LastName=LastName;
this.Email=Email;
}
public String getCode() { return this.Code;}
public String getFirstName() { return this.FirstName;}
public String getLastName() { return this.LastName;}
public String getEmail() {return this.Email;}

public void setCode(String Code) {this.Code=Code;}
public void setFirstName(String FirstName) {this.FirstName=FirstName;}
public void setLastName(String LastName) {this.LastName=LastName;}
public void setEmail(String Email) { this.Email=Email;}

@Override
public String toString() { return this.LastName+ " "+this.FirstName+"("+this.Code+"); }
}
  • Under the root package, add a new one : dao
  • Add a new interface: IEmployeeDAO
package list2xml.dao;

import java.util.List;
import list2xml.model.Employee;

public interface IEmployeeDAO {
   public List InitEmployees();
}
  • Add an implementation class : EmployeeImplementation:
package list2xml.dao;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import list2xml.model.Employee;

public class EmployeeImplementation implements Serializable, IEmployeeDAO{

@Override
public List InitEmployees() {
List l=new ArrayList<>();
l.add(new Employee("EMP-022019", "Jane", "ADAMS", "jane.adams@acme.com"));
l.add(new Employee("EMP-072016", "John", "ADAMS", "john.adams@acme.com"));
return l;
}}

This class implements Serializable and IEmployeeDAO interfaces and has 1 override method : InitEmployees that initialize a List of Employees with random details.

  • On the root package, add a new one : exporter
  • Create a new Java class : EmployeeXmlExporter
package list2xml.exporter;

import java.io.FileWriter;
import java.io.IOException;
import java.util.Date;
import java.util.List;
import list2xml.dao.EmployeeImplementation;
import list2xml.dao.IEmployeeDAO;
import list2xml.model.Employee;

public class EmployeeXmlExporter {

IEmployeeDAO employeeDAO=new EmployeeImplementation();

final String FIELD_CODE="CODE";
final String FIELD_FIRST_NAME="FIRSTNAME";
final String FIELD_LAST_NAME="LASTNAME";
final String FIELD_EMAIL="EMAIL";

public EmployeeXmlExporter() {}

public void Export2Xml(List l) throws IOException {
FileWriter fw=new FileWriter("employees.xml");
StringBuilder sb=new StringBuilder();

sb.append("");

l=employeeDAO.InitEmployees();
for(Employee emp : l) {
sb.append("");
sb.append("<"+FIELD_CODE+">"+emp.getCode()+"</"+FIELD_CODE+">");
sb.append("<"+FIELD_FIRST_NAME+">"+emp.getFirstName()+"</"+FIELD_FIRST_NAME+">");
sb.append("<"+FIELD_LAST_NAME+">"+emp.getLastName()+"</"+FIELD_LAST_NAME+">");
sb.append("<"+FIELD_EMAIL+">"+emp.getEmail()+"</"+FIELD_EMAIL+">");
sb.append("");
}
sb.append("");
fw.write(sb.toString());
fw.flush();
fw.close();
}}

This class has one default constructor, one instance of EmployeeImplementation class and the method Export2Xml that export a given ArrayList of Employees to an XML file.

  • Under the root package, create a new package : main
  • Create under the same package a new class : Main
package list2xml.main;

import java.io.IOException;
import list2xml.dao.EmployeeImplementation;
import list2xml.dao.IEmployeeDAO;
import list2xml.exporter.EmployeeXmlExporter;

public class Main {
  public static void main(String[] a) {
    IEmployeeDAO employeeDAO=new EmployeeImplementation();
    EmployeeXmlExporter employeeXML=new EmployeeXmlExporter();

    try {
     employeeXML.Export2Xml(employeeDAO.InitEmployees());
    }
    catch(IOException ex) {
     ex.printStackTrace();
}}}

This class have the main(String[ ]) method and also, the implementation of the XML export process.

Any remarks ? Write it below

Thank you !