Parsing an XML document using SAX Parser

Aim:

            To create simple SAX parser to parse XML document

Algorithm:

1. Create a Sax parser and parse the xml
2. In the event handler create the employee object
3. Print out the data

Program:

SAXParserExample.java

import java.io.IOException;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

public class SAXParserExample extends DefaultHandler{

            List myEmpls;

           

            private String tempVal;

           

            //to maintain context

            private Employee tempEmp;

           

           

            public SAXParserExample(){

                        myEmpls = new ArrayList();

            }

           

            public void runExample() {

                        parseDocument();

                        printData();

            }

            private void parseDocument() {

                       

                        //get a factory

                        SAXParserFactory spf = SAXParserFactory.newInstance();

                        try {

                       

                                    //get a new instance of parser

                                    SAXParser sp = spf.newSAXParser();

                                   

                                    //parse the file and also register this class for call backs

                                    sp.parse("employees.xml", this);

                                   

                        }catch(SAXException se) {

                                    se.printStackTrace();

                        }catch(ParserConfigurationException pce) {

                                    pce.printStackTrace();

                        }catch (IOException ie) {

                                    ie.printStackTrace();

                        }

            }

            /**

             * Iterate through the list and print

             * the contents

             */

            private void printData(){

                       

                        System.out.println("No of Employees '" + myEmpls.size() + "'.");

                       

                        Iterator it = myEmpls.iterator();

                        while(it.hasNext()) {

                                    System.out.println(it.next().toString());

                        }

            }

           

            //Event Handlers

            public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

                        //reset

                        tempVal = "";

                        if(qName.equalsIgnoreCase("Employee")) {

                                    //create a new instance of employee

                                    tempEmp = new Employee();

                                    tempEmp.setType(attributes.getValue("type"));

                        }

            }

           

            public void characters(char[] ch, int start, int length) throws SAXException {

                        tempVal = new String(ch,start,length);

            }

           

            public void endElement(String uri, String localName, String qName) throws SAXException {

                        if(qName.equalsIgnoreCase("Employee")) {

                                    //add it to the list

                                    myEmpls.add(tempEmp);

                                   

                        }else if (qName.equalsIgnoreCase("Name")) {

                                    tempEmp.setName(tempVal);

                        }else if (qName.equalsIgnoreCase("Id")) {

                                    tempEmp.setId(Integer.parseInt(tempVal));

                        }else if (qName.equalsIgnoreCase("Age")) {

                                    tempEmp.setAge(Integer.parseInt(tempVal));

                        }

                       

            }

           

            public static void main(String[] args){

                        SAXParserExample spe = new SAXParserExample();

                        spe.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>