View xml file in java

How to Read XML File in Java

1. Sample XML File
2. Read XML File Using DocumentBuilderFactory in Java
3. Read XML File in Java POJO
4. Read XML File Using jdom2 in Java
5. Read XML File Using XPath in Java
6. Read XML File Using DOM4J in Java

In this article, we will learn how to parse XML file into Java application by using some libraries such as DOM Parser , XML Parser , jdom2 , dom4j , etc. XML stands for Extensible Markup Language , which is used to pass data in an application.

Sample XML File

This is a sample XML file that will be used to read in this article.

xml version="1.0"?> company>  employee id="1001">  firstname>Tonyfirstname>  lastname>Blacklastname>  salary>100000salary>  employee>  employee id="2001">  firstname>Amyfirstname>  lastname>Greenlastname>  salary>200000salary>  employee> company> 

Read XML File Using DocumentBuilderFactory in Java

We use DocumentBuilder to create an instance for the builder and then parse the XML file using the parse() method. The getElementsByTagName() method fetches each node of the XML, and then each child node of the node is iterated by using the for loop. See the example below.

import java.io.File; import java.io.IOException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException;  public class SimpleTesting   public static void main(String[] args) throws ParserConfigurationException, SAXException    try   File file = new File("company.xml");  DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  DocumentBuilder db = dbf.newDocumentBuilder();  Document document = db.parse(file);  document.getDocumentElement().normalize();  System.out.println("Root Element :" + document.getDocumentElement().getNodeName());  NodeList nList = document.getElementsByTagName("employee");  System.out.println("----------------------------");  for (int temp = 0; temp  nList.getLength(); temp++)   Node nNode = nList.item(temp);  System.out.println("\nCurrent Element :" + nNode.getNodeName());  if (nNode.getNodeType() == Node.ELEMENT_NODE)   Element eElement = (Element) nNode;  System.out.println("Employee id : " + eElement.getAttribute("id"));  System.out.println("First Name : " + eElement.getElementsByTagName("firstname").item(0).getTextContent());  System.out.println("Last Name : " + eElement.getElementsByTagName("lastname").item(0).getTextContent());  System.out.println("Salary : " + eElement.getElementsByTagName("salary").item(0).getTextContent());  >  >  >  catch(IOException e)   System.out.println(e);  >  > > 

Root Element :company ---------------------------- Current Element :employee Employee id : 1001 First Name : Tony Last Name : Black Salary : 100000  Current Element :employee Employee id : 2001 First Name : Amy Last Name : Green Salary : 200000 

Read XML File in Java POJO

In case we want to get XML data into Java-compatible type, we can use Java POJO to read data. Here, we use the ArrayList type Employee to add each node using the add() method and then use the for loop to iterate each object. See the below example.

import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.List; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException;  public class Main   public static void main(String[] args) throws ParserConfigurationException,  SAXException, IOException   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();  DocumentBuilder builder = factory.newDocumentBuilder();  Document document = builder.parse(new File("employee.xml"));  ListEmployee> employees = new ArrayList<>();  NodeList nodeList = document.getDocumentElement().getChildNodes();  for (int i = 0; i  nodeList.getLength(); i++)   Node node = nodeList.item(i);  if (node.getNodeType() == Node.ELEMENT_NODE)   Element elem = (Element) node;  String firstname = elem.getElementsByTagName("firstname")  .item(0).getChildNodes().item(0).getNodeValue();  String lastname = elem.getElementsByTagName("lastname").item(0)  .getChildNodes().item(0).getNodeValue();  Double salary = Double.parseDouble(elem.getElementsByTagName("salary")  .item(0).getChildNodes().item(0).getNodeValue());  employees.add(new Employee(firstname, lastname, salary));  >  >  for (Employee empl: employees)  System.out.println(empl.toString());  > > class Employee   private String Firstname;  private String Lastname;  private double salary;  public Employee(String Firstname, String Lastname, double salary)   this.Firstname = Firstname;  this.Lastname = Lastname;  this.salary = salary;  >  @Override  public String toString()   return "[" + Firstname + ", " + Lastname + ", "+ salary + "]";  > > 

[Tony, Black, 100000.0] [Amy, Green, 200000.0] 

Read XML File Using jdom2 in Java

The jdom2 is a library that provides support of DOM parsing using Java classes. We used SAXBuilder class and build() method to get data into Document and then by using the getRootElement() method, get the elements. See the example below.

import java.io.File; import java.io.IOException; import java.util.List; import javax.xml.parsers.ParserConfigurationException; import org.jdom2.Document; import org.jdom2.Element; import org.jdom2.JDOMException; import org.jdom2.input.SAXBuilder; import org.xml.sax.SAXException;  public class Main   public static void main(String[] args) throws ParserConfigurationException,  SAXException, IOException   try   File inputFile = new File("/employee.xml");  SAXBuilder saxBuilder = new SAXBuilder();  Document document = saxBuilder.build(inputFile);  System.out.println("Root element :" + document.getRootElement().getName());  Element classElement = document.getRootElement();   ListElement> studentList = classElement.getChildren();  System.out.println("----------------------------");   for (int temp = 0; temp  studentList.size(); temp++)   Element student = studentList.get(temp);  System.out.println("\nCurrent Element :"  + student.getName());  System.out.println("First Name : "  + student.getChild("firstname").getText());  System.out.println("Last Name : "  + student.getChild("lastname").getText());  System.out.println("Salary : "  + student.getChild("salary").getText());  >  > catch(JDOMException e)   e.printStackTrace();  > catch(IOException ioe)   ioe.printStackTrace();  >  > > 

Root element :company ---------------------------- Current Element :employee First Name : Tony Last Name : Black Salary : 100000  Current Element :employee First Name : Amy Last Name : Green Salary : 200000 

Read XML File Using XPath in Java

Here, we use the XPath library to parse XML files in Java. The XPathFactory class is used to compile all the nodes into NodeList and then iterate each child through for loop. See the example below.

import java.io.File; import java.io.IOException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException;  public class Main   public static void main(String[] args) throws ParserConfigurationException,  SAXException, IOException   try   File inputFile = new File("/employee.xml");  DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();  DocumentBuilder dBuilder;  dBuilder = dbFactory.newDocumentBuilder();  Document doc = dBuilder.parse(inputFile);  doc.getDocumentElement().normalize();  XPath xPath = XPathFactory.newInstance().newXPath();  String expression = "/company/employee";  NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(  doc, XPathConstants.NODESET);  for (int i = 0; i  nodeList.getLength(); i++)   Node nNode = nodeList.item(i);  System.out.println("\nCurrent Element :" + nNode.getNodeName());  if (nNode.getNodeType() == Node.ELEMENT_NODE)   Element eElement = (Element) nNode;  System.out.println("First Name : "  + eElement  .getElementsByTagName("firstname")  .item(0)  .getTextContent());  System.out.println("Last Name : "  + eElement  .getElementsByTagName("lastname")  .item(0)  .getTextContent());  System.out.println("Salary : "  + eElement  .getElementsByTagName("salary")  .item(0)  .getTextContent());  >  >  > catch (ParserConfigurationException e)   System.out.println(e);  > catch (SAXException e)   System.out.println(e);  > catch (IOException e)   System.out.println(e);  > catch (XPathExpressionException e)   System.out.println(e);  >  > > 

Current Element :employee First Name : Tony Last Name : Black Salary : 100000  Current Element :employee First Name : Amy Last Name : Green Salary : 200000 

Read XML File Using DOM4J in Java

The Dom4j is another library that can parse XML files in Java. The read() method of SAXReader class is used to read nodes into the document. See the example below.

import java.io.File; import java.io.IOException; import java.util.List; import javax.xml.parsers.ParserConfigurationException; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.Element; import org.dom4j.Node; import org.dom4j.io.SAXReader; import org.xml.sax.SAXException;  public class Main   public static void main(String[] args) throws ParserConfigurationException,  SAXException, IOException   try   File inputFile = new File("employee.xml");  SAXReader reader = new SAXReader();  Document document = reader.read( inputFile );  System.out.println("Root element :" + document.getRootElement().getName());  Element classElement = document.getRootElement();  ListNode> nodes = document.selectNodes("company/employee");  System.out.println("----------------------------");  for (Node node : nodes)   System.out.println("\nCurrent Element :"  + node.getName());  System.out.println("First Name : "  + node.selectSingleNode("firstname").getText());  System.out.println("Last Name : "  + node.selectSingleNode("lastname").getText());  System.out.println("Salary : "  + node.selectSingleNode("salary").getText());  >  > catch (DocumentException e)   e.printStackTrace();  >  > > 

Root element :company ---------------------------- Current Element :employee First Name : Tony Last Name : Black Salary : 100000  Current Element :employee First Name : Amy Last Name : Green Salary : 200000 

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