Create your first Java function in Azure using IntelliJ

This article shows you how to use Java and IntelliJ to create an Azure function.

Specifically, this article shows you:

  • How to create an HTTP-triggered Java function in an IntelliJ IDEA project.
  • Steps for testing and debugging the project in the integrated development environment (IDE) on your own computer.
  • Instructions for deploying the function project to Azure Functions.

Prerequisites

Install plugin and sign in

To install the Azure Toolkit for IntelliJ and then sign in, follow these steps:

  1. In IntelliJ IDEA's Settings/Preferences dialog (Ctrl+Alt+S), select Plugins. Then, find the Azure Toolkit for IntelliJ in the Marketplace and click Install. After it's installed, click Restart to activate the plugin.

    Azure Toolkit for IntelliJ plugin in Marketplace.

  2. To sign in to your Azure account, open the Azure Explorer sidebar, and then click the Azure Sign In icon in the bar on top (or from the IDEA menu, select Tools > Azure > Azure Sign in).

    The IntelliJ Azure Sign In command.

  3. In the Azure Sign In window, select OAuth 2.0, and then click Sign in. For other sign-in options, see Sign-in instructions for the Azure Toolkit for IntelliJ.

    The Azure Sign In window with device login selected.

  4. In the browser, sign in with your account and then go back to IntelliJ. In the Select Subscriptions dialog box, click on the subscriptions that you want to use, then click Select.

    The Select Subscriptions dialog box.

Create your local project

To use Azure Toolkit for IntelliJ to create a local Azure Functions project, follow these steps:

  1. Open IntelliJ IDEA's Welcome dialog, select New Project to open a new project wizard, then select Azure Functions.

    Create function project.

  2. Select Http Trigger, then click Next and follow the wizard to go through all the configurations in the following pages. Confirm your project location, then click Finish. Intellj IDEA will then open your new project.

    Create function project finish.

Run the project locally

To run the project locally, follow these steps:

  1. Navigate to src/main/java/org/example/functions/HttpTriggerFunction.java to see the code generated. Beside the line 24, you'll notice that there's a green Run button. Click it and select Run 'Functions-azur...'. You'll see that your function app is running locally with a few logs.

    Local run project.

    Local run project output.

  2. You can try the function by accessing the displayed endpoint from browser, such as http://localhost:7071/api/HttpExample?name=Azure.

    Local run function test result.

  3. The log is also displayed in your IDEA. Stop the function app by clicking the Stop button.

    Local run function test log.

Debug the project locally

To debug the project locally, follow these steps:

  1. Select the Debug button in the toolbar. If you don't see the toolbar, enable it by choosing View > Appearance > Toolbar.

    Local debug function app button.

  2. Click on line 31 of the file src/main/java/org/example/functions/HttpTriggerFunction.java to add a breakpoint. Access the endpoint http://localhost:7071/api/HttpTrigger-Java?name=Azure again and you'll find the breakpoint is hit. You can then try more debug features like Step, Watch, and Evaluation. Stop the debug session by clicking the Stop button.

    Local debug function app break.

Deploy your project to Azure

To deploy your project to Azure, follow these steps:

  1. Right click your project in IntelliJ Project explorer, then select Azure -> Deploy to Azure Functions.

    Deploy project to Azure.

  2. If you don't have any Function App yet, click + in the Function line. Type in the function app name and choose proper platform. Here you can accept the default value. Click OK and the new function app you created will be automatically selected. Click Run to deploy your functions.

    Create function app in Azure.

    Deploy function app to Azure log.

Manage function apps from IDEA

To manage your function apps with Azure Explorer in your IDEA, follow these steps:

  1. Click on Function App and you'll see all your function apps listed.

    View function apps in explorer.

  2. Click to select on one of your function apps, then right click and select Show Properties to open the detail page.

    Show function app properties.

  3. Right click on your HttpTrigger-Java function app, then select Trigger Function in Browser. You'll see that the browser is opened with the trigger URL.

    Screenshot shows a browser with the U R L.

Add more functions to the project

To add more functions to your project, follow these steps:

  1. Right click on the package org.example.functions and select New -> Azure Function Class.

    Add functions to the project entry.

  2. Fill in the class name HttpTest and select HttpTrigger in the create function class wizard, then click OK to create. In this way, you can create new functions as you want.

    Screenshot shows the Create Function Class dialog box.

    Add functions to the project output.

Cleaning up functions

Select one of your function apps using Azure Explorer in your IDEA, then right-click and select Delete. This command might take several minutes to run. When it's done, the status will refresh in Azure Explorer.

Screenshot shows Delete selected from a context menu.

Next steps

You've created a Java project with an HTTP triggered function, run it on your local machine, and deployed it to Azure. Now, extend your function by continuing to the following article: