Step by Step Guide to Building a Holded API Integration in Java

Introduction

Hey there, fellow developer! Ready to dive into the world of Holded API integration? You're in for a treat. Holded's API is a powerful tool that'll let you tap into their business management platform, and we're going to build that integration using Java. Buckle up!

Prerequisites

Before we jump in, make sure you've got:

• A Java development environment (I know you've got this covered)
• A Holded account with API credentials (if you don't have one, go grab it!)
• An HTTP client library (we'll be using OkHttp, but feel free to use your favorite)

Setting up the project

Let's get this show on the road:

1. Fire up your IDE and create a new Java project.
2. Add the OkHttp dependency to your pom.xml:

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.10.0</version>
</dependency>

Authentication

Alright, time to get cozy with Holded:

1. Grab your API key from your Holded account.
2. Create a constant for your API key:

private static final String API_KEY = "your_api_key_here";

3. We'll use this in our requests. Speaking of which...

Making API requests

Let's start talking to Holded:

OkHttpClient client = new OkHttpClient();

Request request = new Request.Builder()
    .url("https://api.holded.com/api/invoices/v1/invoices")
    .addHeader("key", API_KEY)
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
} catch (IOException e) {
    e.printStackTrace();
}

This GET request will fetch your invoices. For POST requests, you'll need to add a request body. Easy peasy!

Implementing key Holded API endpoints

Now, let's get our hands dirty with some specific endpoints:

Contacts

// GET all contacts
Request request = new Request.Builder()
    .url("https://api.holded.com/api/invoicing/v1/contacts")
    .addHeader("key", API_KEY)
    .build();

// POST a new contact
String json = "{\"name\":\"John Doe\",\"email\":\"[email protected]\"}";
RequestBody body = RequestBody.create(json, MediaType.parse("application/json"));
Request request = new Request.Builder()
    .url("https://api.holded.com/api/invoicing/v1/contacts")
    .addHeader("key", API_KEY)
    .post(body)
    .build();

Invoices

// GET all invoices
Request request = new Request.Builder()
    .url("https://api.holded.com/api/invoicing/v1/invoices")
    .addHeader("key", API_KEY)
    .build();

// POST a new invoice
String json = "{\"contactId\":\"contact_id\",\"items\":[{\"name\":\"Item 1\",\"units\":1,\"price\":100}]}";
RequestBody body = RequestBody.create(json, MediaType.parse("application/json"));
Request request = new Request.Builder()
    .url("https://api.holded.com/api/invoicing/v1/invoices")
    .addHeader("key", API_KEY)
    .post(body)
    .build();

You get the idea! Rinse and repeat for other endpoints like Products, Orders, etc.

Error handling and best practices

Don't forget to handle those pesky errors:

if (!response.isSuccessful()) {
    throw new IOException("Unexpected code " + response);
}

And remember, Holded has rate limits. Be a good API citizen and don't hammer their servers!

Testing the integration

Time to make sure everything's working smoothly:

1. Write unit tests for your API wrapper methods.
2. Create integration tests that actually hit the Holded API (use a test account for this).

Conclusion

And there you have it! You've just built a Holded API integration in Java. Pretty cool, right? From here, you can expand on this foundation to create more complex integrations. The sky's the limit!

Resources

• Holded API Documentation
• OkHttp

Now go forth and integrate! And remember, if you get stuck, the Holded docs and the developer community are your friends. Happy coding!