Source Code:
DomParserExample.java
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
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.NodeList;
import org.xml.sax.SAXException;
public class DomParserExample
{
//No generics
List myEmpls;
Document dom;
public DomParserExample()
{
//create a list to hold the employee objects
myEmpls = new ArrayList();
}
public void runExample()
{
//parse the xml file and get the dom object
parseXmlFile();
//get each employee element and create a Employee object
parseDocument();
//Iterate through the list and print the data
printData();
}
private void parseXmlFile()
{
//get the factory
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
//Using factory get an instance of document builder
DocumentBuilder db = dbf.newDocumentBuilder();
//parse using builder to get DOM representation of the XML file
dom = db.parse("employees.xml");
}
catch(ParserConfigurationException pce) {pce.printStackTrace();}
catch(SAXException se) {se.printStackTrace();}
catch(IOException ioe) {ioe.printStackTrace();}
}
private void parseDocument()
{
//get the root elememt
Element docEle = dom.getDocumentElement();
//get a nodelist of <employee> elements
NodeList nl = docEle.getElementsByTagName("Employee");
if(nl != null && nl.getLength() > 0)
{
for(int i = 0 ; i < nl.getLength();i++)
{
//get the employee element
Element el = (Element)nl.item(i);
//get the Employee object
Employee em = getEmployee(el);
//add it to list
myEmpls.add(em);
}
}
}
/**
* I take an employee element and read the values in, create
* an Employee object and return it
* @param empEl
* @return
*/
private Employee getEmployee(Element empEl)
{
//for each <employee> element get text or int values of
//name ,id, age and name
String name = getTextValue(empEl,"Name");
int id = getIntValue(empEl,"Id");
int age = getIntValue(empEl,"Age");
String type = empEl.getAttribute("type");
//Create a new Employee with the value read from the xml nodes
Employee e = new Employee(name,id,age,type);
return e;
}
/**
* I take a xml element and the tag name, look for the tag and get
* the text content
* i.e for <employee><name>John</name></employee> xml snippet if
* the Element points to employee node and tagName is name I will return John
* @param ele
* @param tagName
* @return
*/
private String getTextValue(Element ele, String tagName)
{
String textVal = null;
NodeList nl = ele.getElementsByTagName(tagName);
if(nl != null && nl.getLength() > 0)
{
Element el = (Element)nl.item(0);
textVal = el.getFirstChild().getNodeValue();
}
return textVal;
}
/**
* Calls getTextValue and returns a int value
* @param ele
* @param tagName
* @return
*/
private int getIntValue(Element ele, String tagName)
{
//in production application you would catch the exception
return Integer.parseInt(getTextValue(ele,tagName));
}
/**
* Iterate through the list and print the
* content to console
*/
private void printData()
{
System.out.println("No of Employees '" + myEmpls.size() + "'.");
Iterator it = myEmpls.iterator();
while(it.hasNext())
{
System.out.println(it.next().toString());
}
}
public static void main(String[] args)
{
//create an instance
DomParserExample dpe = new DomParserExample();
//call run example
dpe.runExample();
}}
Employee.java
public class Employee {
private String name;
private int age;
private int id;
private String type;
public Employee(){
}
public Employee(String name, int id, int age,String type) {
this.name = name;
this.age = age;
this.id = id;
this.type = type;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("Employee Details - ");
sb.append("Name:" + getName());
sb.append(", ");
sb.append("Type:" + getType());
sb.append(", ");
sb.append("Id:" + getId());
sb.append(", ");
sb.append("Age:" + getAge());
sb.append(".");
return sb.toString();
}
}
employees.xml
<?xml version="1.0" encoding="UTF-8"?>
<Personnel>
<Employee type="permanent">
<Name>Seagull</Name>
<Id>3674</Id>
<Age>34</Age>
</Employee>
<Employee type="contract">
<Name>Robin</Name>
<Id>3675</Id>
<Age>25</Age>
</Employee>
<Employee type="permanent">
<Name>Crow</Name>
<Id>3676</Id>
<Age>28</Age>
</Employee>
</Personnel>
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