How to parse xml file using DOM parser in java

               Parsing is a process which reads the XML document and interprets it. It extracts the data from the xml and make it in usable format for the program.

Let us create an XML file for customers.

“Customers.xml”

<Customers>

  <customer>

    <name>Rajeeva</name>

    <id>c_1</id>

  </customer>

  <customer>

    <name>Jey</name>

    <id>c_2</id>

  </customer>

 <customer>

    <name>Sandha</name>

    <id>c_3</id>

  </customer>

</Customers>

Here, the root node is  ‘Customers’. It has elements ‘customer’ with data ‘name’ and ‘id’.

Let us parse this XML using java program.

To parse the XML file in java, DOM(Document Object Model) is used.

Steps to follow:

• Import the built in packages javax.xml.parsers.DocumentBuilder, javax.xml.parsers.DocumentBuilderFactory and org.w3c.dom.
• Create a public class with main() function.
• Using a try,catch block, add the code.
• Initially, the xml file is opened by the DOM. For doing this, create an object for  DocumentBuilderFactory as new instance.
• Using this instance,call the newDocumentBuilder() function and assign it to DocumentBuilder object.
• This object’s function parse opens the xml file and assign it to the Document object.
• A NodeList object is created and reads the xml document elements.
• Using a for loop, the following process is repeated.
•  Each  and every elements in the node is read separately and printed.

Program:

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.*;

public class ReadXMLFileEg {

    public static void main(String[] args) {

        try {

            DocumentBuilderFactory factory1 = DocumentBuilderFactory.newInstance();

            DocumentBuilder builder1 = factory1.newDocumentBuilder();

            Document doc1 = builder1.parse("Customers.xml");

            NodeList customerList1 = doc1.getElementsByTagName("customer");

            for (int i = 0; i < customerList1.getLength(); i++) {

                org.w3c.dom.Node node = customerList1.item(i);

                if (node.getNodeType() == org.w3c.dom.Node.ELEMENT_NODE) {

                    Element customer = (Element) node;

                    String name = customer.getElementsByTagName("name").item(0).getTextContent();

                    String id = customer.getElementsByTagName("id").item(0).getTextContent();

                    System.out.println("Customer Name: " + name + ",Customer id: " + id);

                }

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

Output:

Compile and run the java program to get the output.

C:\raji\blog>javac ReadXMLFileEg.java

C:\raji\blog>java ReadXMLFileEg

Customer Name: Rajeeva,Customer id: c_1

Customer Name: Jey,Customer id: c_2

Customer Name: Sandha,Customer id: c_3

 Note: both xml and java files should be saved in the same directory.

Hope this code to parse the xml file in java is useful to you. Feel free to ask your queries. Keep Coding!!!

Banking application in java

 Let us create a banking application in java. A banking application needs the following.

Member variables:

An account: customer name, account number and deposit amount.

Member functions:

‘deposit()’ – it deposits the amount to the account.

‘withdraw()’ – it withdraws the amount from the account.

‘display the details()’ -this function displays the account details.

import java.util.Scanner;

public class BankingEg {

    private String CustomerName;

    private int account_no;

    private double balance;

    public BankingEg(String name, int account_no, double init_Balance) {

        this.CustomerName = name;

        this.account_no = account_no;

        this.balance = init_Balance;

    }

    public void deposit(double amount) {

        if (amount > 0) {

            balance += amount;

            System.out.println("Deposit successful! Your Current balance is: " + balance);

        } else {

            System.out.println("Sorry. It's a Invalid deposit amount.");

        }

    }

    public void withdraw(double amount) {

        if (amount > 0 && amount <= balance) {

            balance -= amount;

            System.out.println("Withdrawal successful! Your Current balance is: " + balance);

        } else {

            System.out.println("Sorry.Amount is Insufficient");

        }

    }

    public void displayIt() {

        System.out.println("\nAccount Details:");

        System.out.println("Account Holder Name: " + CustomerName);

        System.out.println("Account Number: " + account_no);

        System.out.println("Current Balance: " + balance);

    }

    public static void main(String[] args) {

        Scanner s1 = new Scanner(System.in);

        // Creating the account

        System.out.print("Enter the name of account holder: ");

        String name = s1.nextLine();

        System.out.print("Enter the account number: ");

        int account_no = s1.nextInt();

        System.out.print("Enter the initial deposit amount: ");

        double init_Balance = s1.nextDouble();

        BankingEg b1 = new BankingEg(name, account_no, init_Balance);

        // Display menu

        while (true) {

            System.out.println("\nXYZ Banking:");

            System.out.println("1. Deposit");

            System.out.println("2. Withdraw");

            System.out.println("3. Display the Account Details");

            System.out.println("4. Exit");

            System.out.print("Choose an option: ");

            int choice = s1.nextInt();

            switch (choice) {

                case 1:

                    System.out.print("Enter the deposit amount: ");

                    double depositAmount = s1.nextDouble();

                    b1.deposit(depositAmount);

                    break;

                case 2:

                    System.out.print("Enter the withdrawal amount: ");

                    double withdrawalAmount = s1.nextDouble();

                    b1.withdraw(withdrawalAmount);

                    break;

                case 3:

                    b1.displayIt();

                    break;

                case 4:

                    System.out.println("Thank you for using the banking application!");

                    s1.close();

                    return;

                default:

                    System.out.println("Invalid option. Please try again.");

            }

        }

    }

}

Output:

Here ,is the output.

C:\raji\blog>javac BankingEg.java

C:\raji\blog>java BankingEg

Enter the name of account holder: Rajeswari

Enter the account number: 123

Enter the initial deposit amount: 24000

XYZ Banking:

1. Deposit

2. Withdraw

3. Display the Account Details

4. Exit

Choose an option: 1

Enter the deposit amount: 2500

Deposit successful! Your Current balance is: 26500.0

XYZ Banking:

1. Deposit

2. Withdraw

3. Display the Account Details

4. Exit

Choose an option: 2

Enter the withdrawal amount: 1500

Withdrawal successful! Your Current balance is: 25000.0

XYZ Banking:

1. Deposit

2. Withdraw

3. Display the Account Details

4. Exit

Choose an option: 3

Account Details:

Account Holder Name: Rajeswari

Account Number: 123

Current Balance: 25000.0

XYZ Banking:

1. Deposit

2. Withdraw

3. Display the Account Details

4. Exit

Choose an option: 4

Thank you for using the banking application!

This is the simple Banking application implemented in java. Hope this code is useful to you. Keep coding!!!