Building the Best Currency Converter App in Java

Have you ever wondered how much your money is worth in different countries? Imagine instantly converting dollars to euros or yen with just a few taps on your phone. Well, get ready to dive into the exciting world of coding as we embark on a journey to create the best Currency Converter App using Java and the powerful Fixer API. In this blog, we will discuss building your best currency converter app. Hence, you can get accurate foreign exchange rates.

Even if you’re new to programming, fear not! We’ll use simple words and short sentences to ensure you can follow along. Java, a popular programming language, will be our tool of choice. It’s like giving instructions to your computer in a language it understands. And the Fixer API? Think of it as a magical data source with up-to-date foreign exchange rates.

We’ll start by setting up the basic structure of our app and then gradually add the code to fetch real-time exchange rates from the Fixer API. You’ll witness firsthand how small bits of code combine to create a fully functional app to convert currencies in a snap. So, if you’re curious about coding, currencies, and creating your cool app, buckle up! Let’s begin the exciting journey of building a Currency Converter App using Java and the Fixer API.

What Is a Currency Converter App?

A Currency Converter App is like a digital money translator for your phone or computer. It helps you figure out how much money from one country is worth in another country. You can type in an amount of money in your currency, like dollars, and the app instantly shows you how many euros, yen, or any other currency you’d get.

It’s like having a super quick way to know how valuable your money is in different places. So, if you’re planning a trip or just curious about money worldwide, a Currency Converter App is a handy tool!

What Are the Applications Of a Currency Converter App?

Imagine you’re planning a dream vacation to a far-off land. You’ve saved up some money, but wait! How do you know how much those dollars will be worth in a different country? That’s where a Currency Converter App comes to the rescue!

Let’s explore some of its amazing applications.

1. Travel Buddies

When you’re jetting off to a new place, you can quickly convert your home currency to the local one. This helps you budget for meals, souvenirs, and exciting adventures without any currency confusion.

2. Shopping Savvy

Have you ever wanted to buy something online from a different country? The currency converter app can help you compare prices in your currency. Hence making sure you’re getting the best deal.

3. Money Matters

Suppose you’re into stocks, trading, or just curious about global economics. In that case, the app can help you keep track of currency values and changes. Hence, giving you a better understanding of the financial world.

4. Budgeting Bliss

Whether saving up for a new gaming console or planning a big celebration, the currency converter app can help you set goals. Moreover, it can keep track of your progress, no matter where you are.

5. Math Magic

Hey, math enthusiasts! The app is like a mini math wizard that lets you practice multiplication and division while having fun converting currencies.

Currency Converter App isn’t just about money but about simplifying your life. Therefore helping you make smart choices and explore the exciting world of numbers in a new way.

Why Should We Choose Java To Create Currency Converter Apps?

So, you’re all set to dive into the app creation world and wonder which tool to use. Look no further – Java is your go-to superhero! Java is a reliable friend you can always count on when building cool stuff, like Currency Converter Apps.

Java is super popular and widely used in the coding universe. It’s like the common language that computers understand. Hence, making it easier for you to talk to them and create amazing things. Plus, it’s like building with Lego bricks – you can combine different pieces to create something extraordinary.

When it comes to currency converters, Java shines like a star. It’s got these special powers called libraries that can do all sorts of math tricks. Hence, it is perfect for converting currencies! You don’t have to be a math whiz – Java’s got your back.

Oh, and guess what? Java plays nicely with devices like phones, tablets, and computers. So, your Currency Converter App can reach many people, no matter what gadget they’re using.

But that’s not all – Java is like the cool kid who hangs out with everyone. It works smoothly with databases, so you can save and organize all the currency data you need. Plus, it’s got a bunch of helpful friends (called frameworks) that can make your app-building journey even easier.

So, there you have it – Java is your trusty sidekick for creating Currency Converter Apps. It’s like the magic wand you wave to turn your coding dreams into reality. It’s time to start your coding adventure with Java and create an app that can convert currencies faster than a speedster!

How to Set Up the Development Environment?

Setting up the stage for building your Currency Converter App is as easy as pie! Just follow these simple steps to get your development environment ready.

Installing Java Development Kit (JDK)

First off, we need the Java Development Kit (JDK) – think of it like the toolbox for crafting our app. Visit the official JDK website, download the version that suits your computer, and follow the installation instructions. It’s like adding the special tools you need for your project.

Registering for a Fixer API access key

Next up, we’ll need a key to unlock the treasure trove of currency exchange rates. Head over to the Fixer API website, sign up for an account (don’t worry, it’s free!), and they’ll hand you an API key. This key is like the secret code that lets your app talk to the Fixer API and fetch real-time currency info.

Remember to keep your access key safe and sound, like a key to a treasure chest! You can start coding your Currency Converter App with your JDK installed and your Fixer API access key.

How to Implement the Currency Conversion Logic Using Java & Fixer API?

First, create a folder where you want to place your Java application.

Then, open it inside the Visual Studio Code.

Next, create a Java file and name it “CurrencyConverter.java.”

Once you create the Java file, follow the below steps to add the code inside this file.

1. Importing Required Libraries

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URI;

import java.net.URISyntaxException;

import org.json.simple.JSONObject;

import org.json.simple.parser.JSONParser;

import org.json.simple.parser.ParseException;

These lines import various Java libraries for handling input, making HTTP requests, and parsing JSON data.

2. Defining the Class and Constants

public class CurrencyConverter {

    private static final String API_KEY = "YOURAPIKEY";

    private static final String BASE_URL = "http://data.fixer.io/api/latest";

Here, a class named `CurrencyConverter` is defined. It contains two constants: `API_KEY`, which stores the access key for the Fixer API, and `BASE_URL`, which is the base URL of the API.

3. `convertCurrency` Method

public double convertCurrency(String fromCurrency, String toCurrency, double amount) throws IOException, URISyntaxException, ParseException {

This method takes three parameters: `fromCurrency`, `toCurrency`, and `amount`. It is designed to convert an amount from one currency to another. The method can throw three types of exceptions: `IOException`, `URISyntaxException`, and `ParseException`.

4. Constructing the API Request and Parsing Response

URI uri = new URI(BASE_URL + "?access_key=" + API_KEY + "&base=" + fromCurrency);

HttpURLConnection connection = (HttpURLConnection) uri.toURL().openConnection();

try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {

    StringBuilder response = new StringBuilder();

    String line;

    while ((line = reader.readLine()) != null) {

        response.append(line);

    }

    JSONParser parser = new JSONParser();

    JSONObject jsonObject = (JSONObject) parser.parse(response.toString());

    JSONObject rates = (JSONObject) jsonObject.get("rates");

    double toCurrencyRate = (Double) rates.get(toCurrency);

    return amount * toCurrencyRate;

}

The method constructs a URL for the API request using the provided base currency. It opens a connection to the URL and reads the API response. The JSON response is parsed using the `JSONParser` class, and the conversion rate for the target currency is extracted. The method then calculates the converted amount and returns it.

5. `main` Method

public static void main(String[] args) {

    CurrencyConverter currencyConverter = new CurrencyConverter();

    try {

        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        // ...

    } catch (IOException | URISyntaxException | ParseException | NumberFormatException e) {

        e.printStackTrace();

    }

}

The `main` method is the entry point of the program. It creates an instance of the `CurrencyConverter` class. It takes user input for the base currency, target currency, and amount and then calls the `convert currency` method to perform the conversion. Any exceptions that occur during this process are caught and printed.

Final Code

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class CurrencyConverter {

    private static final String API_KEY = "43ca5faebc7d179a5d05fc6969b3f340";
    private static final String BASE_URL = "http://data.fixer.io/api/latest";

    public double convertCurrency(String fromCurrency, String toCurrency, double amount) throws IOException, URISyntaxException, ParseException {
        URI uri = new URI(BASE_URL + "?access_key=" + API_KEY + "&base=" + fromCurrency);
        HttpURLConnection connection = (HttpURLConnection) uri.toURL().openConnection();

        try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
            StringBuilder response = new StringBuilder();
            String line;

            while ((line = reader.readLine()) != null) {
                response.append(line);
            }

            JSONParser parser = new JSONParser();
            JSONObject jsonObject = (JSONObject) parser.parse(response.toString());
            JSONObject rates = (JSONObject) jsonObject.get("rates");
            double toCurrencyRate = (Double) rates.get(toCurrency);

            return amount * toCurrencyRate;
        }
    }

    public static void main(String[] args) {
        CurrencyConverter currencyConverter = new CurrencyConverter();

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

            System.out.print("Enter the base currency (e.g., USD): ");
            String fromCurrency = reader.readLine();

            System.out.print("Enter the target currency (e.g., EUR): ");
            String toCurrency = reader.readLine();

            System.out.print("Enter the amount: ");
            double amount = Double.parseDouble(reader.readLine());

            double convertedAmount = currencyConverter.convertCurrency(fromCurrency, toCurrency, amount);
            System.out.println("Converted Amount: " + convertedAmount);

        } catch (IOException | URISyntaxException | ParseException | NumberFormatException e) {
            e.printStackTrace();
        }
    }
}

Create a Folder and Place the Jar File Inside That Folder

The next step is to create a “lib” folder inside the root directory of your Java application.

Inside that folder, you must keep the JAR file. You can get the json-simple-1.1.1.jar file by following the below steps:

You can download the json-simple library from its official website: https://code.google.com/archive/p/json-simple/downloads.

Choose the appropriate version (e.g., json-simple-1.1.1.jar), then place the downloaded .jar file in your project folder.

Once you have made all the above changes, it is time to run the below commands one by one.

javac -cp .;lib\json-simple-1.1.1.jar CurrencyConverter.java
java -cp .;lib\json-simple-1.1.1.jar CurrencyConverter

Your application is ready now. Run and Debug it inside your code compiler.

Output

It will ask you to enter the currencies and the amount. The output will be displayed once you click on enter.

Best Currency Converter App: Conclusion

Building a robust and user-friendly Currency Converter App using Java and the Fixer API offers a powerful tool. This app gives users accurate conversion rates by leveraging Java’s versatility and the Fixer API’s real-time data. Users can effortlessly input their desired currencies and amounts by implementing a well-designed graphical user interface (GUI). Hence, receiving instant and accurate conversion results.

The development process involves integrating the Fixer API, handling JSON data, and designing an intuitive GUI using Java’s Swing library. This combination of technical proficiency and user-centric design ensures a seamless and engaging experience.

Developers can create a Currency Converter App by harnessing the potential of Java and the Fixer API. This app serves a practical purpose and showcases their programming skills in building effective and aesthetically pleasing applications. The resulting app provides a valuable service and highlights the synergy between technology and user convenience.

Best Currency Converter App: FAQs

Which Is the Best Free Currency Converter App?

“The best free currency converter app offers real-time rates, a user-friendly interface, and accurate conversions for seamless international transactions.”

What Is the Best App to Convert Money?

App created using the Fixer API & Java can be among Android users’ best currency converter apps.

What Is the Best Currency Converter App Offline?

An offline currency converter app offers instant conversion without requiring internet connectivity. Hence, enhancing convenience and accessibility.”

Is There an App to Check Currency?

Various currency converter apps are available for checking exchange rates and converting currencies on the go.

Unlock the power of global financial data with Fixer API. Seamlessly integrate real-time exchange rates into your applications. Get started today!