Microservices: Setting Up Currency Conversion Microservice

Introduction

This tutorial walks you through the process of setting up a currency conversion microservice in a microservices architecture. Currency conversion services are common in distributed systems, allowing applications to convert amounts from one currency to another.

Setting Up Currency Conversion Microservice

Prerequisites

Before starting, ensure that you have the following:

• A Java development environment
• Spring Boot installed
• An understanding of microservices architecture concepts

Steps

1. Create a New Spring Boot Project

Use Spring Initializr or your preferred method to create a new Spring Boot project.

2. Define the Currency Conversion Entity

Create a CurrencyConversion entity class representing the data structure for currency conversion.

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class CurrencyConversion {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String fromCurrency;
    private String toCurrency;
    private double conversionRate;
    private double amount;
    private double convertedAmount;

    // Constructors, getters, and setters
}

3. Implement the Currency Conversion Service

Create a service class (CurrencyConversionService) to handle currency conversion logic.

import org.springframework.stereotype.Service;

@Service
public class CurrencyConversionService {

    public double convertCurrency(double amount, double conversionRate) {
        return amount * conversionRate;
    }
}

4. Implement the Currency Conversion Controller

Create a controller class (CurrencyConversionController) to expose REST endpoints for currency conversion.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/currency-conversion")
public class CurrencyConversionController {

    @Autowired
    private CurrencyConversionService currencyConversionService;

    @GetMapping("/convert")
    public double convertCurrency(@RequestParam String from, @RequestParam String to, @RequestParam double amount) {
        // Fetch conversion rate from a service or database (mocked here)
        double conversionRate = 1.2;

        // Perform currency conversion
        return currencyConversionService.convertCurrency(amount, conversionRate);
    }
}

5. Configure Application Properties

Configure database connection and other properties in the application.properties file.

spring.datasource.url=jdbc:mysql://localhost:3306/microservices_db
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.hibernate.ddl-auto=update

Explanation

• CurrencyConversion Entity: Represents the structure of a currency conversion record in the database.
• CurrencyConversionService: Handles the logic for currency conversion.
• CurrencyConversionController: Exposes REST endpoints for currency conversion.

Use

• Currency Conversion Logic: Implement currency conversion logic based on real-time conversion rates.
• Microservices Communication: Integrate this microservice with other microservices for comprehensive functionality.
• Database Storage: Store conversion records in a database for auditing or historical analysis.

Important Points

1. Real-Time Conversion Rates: Integrate with a service or API to fetch real-time conversion rates.
2. Database Interaction: Use JPA repositories to interact with a database for storing conversion records.
3. Microservices Communication: Consider security aspects when implementing communication with other microservices.

Summary

Setting up a currency conversion microservice involves defining entities, implementing services, and exposing REST endpoints. This microservice can be part of a larger ecosystem of microservices, providing currency conversion capabilities to various applications in a distributed architecture.