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Secure Java Spring Boot apps using Microsoft Entra ID

  • Artikkeli

This article demonstrates a Java Spring Boot web app that signs in users on your Microsoft Entra ID tenant using the Microsoft Entra ID Spring Boot Starter client library for Java. It uses the OpenID Connect protocol.

The following diagram shows the topology of the app:

Diagram that shows the topology of the app.

The client app uses the Microsoft Entra ID Spring Boot Starter client library for Java to sign-in a user and obtain an ID token from Microsoft Entra ID. The ID token proves that the user is authenticated with Microsoft Entra ID and enables the user to access protected routes.

Prerequisites

Recommendations

  • Some familiarity with the Spring Framework.
  • Some familiarity with Linux/OSX terminal.
  • jwt.ms for inspecting your tokens.
  • Fiddler for monitoring your network activity and troubleshooting.
  • Follow the Microsoft Entra ID Blog to stay up-to-date with the latest developments.

Set up the sample

The following sections show you how to set up the sample application.

Clone or download the sample repository

To clone the sample, open a Bash window and use the following command:

git clone https://github.com/Azure-Samples/ms-identity-msal-java-samples.git
cd 4-spring-web-app/1-Authentication/sign-in

Alternatively, navigate to the ms-identity-msal-java-samples repository, then download it as a .zip file and extract it to your hard drive.

Important

To avoid path length limitations on Windows, we recommend cloning into a directory near the root of your drive.

Register the sample applications with your Microsoft Entra ID tenant

There's one project in this sample. The following sections show you how to register the app using the Azure portal.

Choose the Microsoft Entra ID tenant where you want to create your applications

To choose your tenant, use the following steps:

  1. Sign in to the Azure portal.

  2. If your account is present in more than one Microsoft Entra ID tenant, select your profile in the corner of the Azure portal, and then select Switch directory to change your session to the desired Microsoft Entra ID tenant.

Register the app (java-spring-webapp-auth)

To register the app, use the following steps:

  1. Navigate to the Azure portal and select Microsoft Entra ID.

  2. Select App Registrations on the navigation pane, then select New registration.

  3. In the Register an application page that appears, enter the following application registration information:

    • In the Name section, enter a meaningful application name for display to users of the app - for example, java-spring-webapp-auth.
    • Under Supported account types, select Accounts in this organizational directory only.
    • In the Redirect URI (optional) section, select Web in the combo-box and enter the following redirect URI: http://localhost:8080/login/oauth2/code/.

  4. Select Register to create the application.

  5. On the app's registration page, find and copy the Application (client) ID value to use later. You use this value in your app's configuration file or files.

  6. On the app's registration page, select Certificates & secrets on the navigation pane to open the page where you can generate secrets and upload certificates.

  7. In the Client secrets section, select New client secret.

  8. Type a description - for example, app secret.

  9. Select one of the available durations: In 1 year, In 2 years, or Never Expires.

  10. Select Add. The generated value is displayed.

  11. Copy and save the generated value for use in later steps. You need this value for your code's configuration files. This value isn't displayed again, and you can't retrieve it by any other means. So, be sure to save it from the Azure portal before you navigate to any other screen or pane.

Configure the app (java-spring-webapp-auth) to use your app registration

Use the following steps to configure the app:

Note

In the following steps, ClientID is the same as Application ID or AppId.

  1. Open the project in your IDE.

  2. Open the src\main\resources\application.yml file.

  3. Find the placeholder Enter_Your_Tenant_ID_Here and replace the existing value with your Microsoft Entra tenant ID.

  4. Find the placeholder Enter_Your_Client_ID_Here and replace the existing value with the application ID or clientId of the java-spring-webapp-auth app copied from the Azure portal.

  5. Find the placeholder Enter_Your_Client_Secret_Here and replace the existing value with the value you saved during the creation of java-spring-webapp-auth copied from the Azure portal.

Run the sample

The following sections show you how to deploy the sample to Azure Container Apps.

Prerequisites

Prepare the Spring project

Use the following steps to prepare the project:

  1. Use the following Maven command to build the project:

    mvn clean verify

  2. Run the sample project locally by using the following command:

    mvn spring-boot:run

Setup

To sign in to Azure from the CLI, run the following command and follow the prompts to complete the authentication process.

az login

To ensure you're running the latest version of the CLI, run the upgrade command.

az upgrade

Next, install or update the Azure Container Apps extension for the CLI.

If you receive errors about missing parameters when you run az containerapp commands in Azure CLI, be sure you have the latest version of the Azure Container Apps extension installed.

az extension add --name containerapp --upgrade

Note

Starting in May 2024, Azure CLI extensions no longer enable preview features by default. To access Container Apps preview features, install the Container Apps extension with --allow-preview true.

az extension add --name containerapp --upgrade --allow-preview true

Now that the current extension or module is installed, register the Microsoft.App and Microsoft.OperationalInsights namespaces.

Note

Azure Container Apps resources have migrated from the Microsoft.Web namespace to the Microsoft.App namespace. Refer to Namespace migration from Microsoft.Web to Microsoft.App in March 2022 for more details.

az provider register --namespace Microsoft.App
az provider register --namespace Microsoft.OperationalInsights

Create the Azure Container Apps environment

Now that your Azure CLI setup is complete, you can define the environment variables that are used throughout this article.

Define the following variables in your bash shell.

export RESOURCE_GROUP="ms-identity-containerapps"
export LOCATION="canadacentral"
export ENVIRONMENT="env-ms-identity-containerapps"
export API_NAME="ms-identity-api"
export JAR_FILE_PATH_AND_NAME="./target/ms-identity-spring-boot-webapp-0.0.1-SNAPSHOT.jar"

Create a resource group.

az group create  \
    --name $RESOURCE_GROUP \
    --location $LOCATION \

Create an environment with an auto-generated Log Analytics workspace.

az containerapp env create \
    --name $ENVIRONMENT \
    --resource-group $RESOURCE_GROUP \
    --location $LOCATION

Show the default domain of the container app environment. Note down this domain to use in later sections.

az containerapp env show \
    --name $ENVIRONMENT \
    --resource-group $RESOURCE_GROUP \
    --query properties.defaultDomain

Prepare the app for deployment

When you deploy your application to Azure Container Apps, your redirect URL changes to the redirect URL of your deployed app instance in Azure Container Apps. Use the following steps to change these settings in your application.yml file:

  1. Navigate to your app's src\main\resources\application.yml file and change the value of post-logout-redirect-uri to your deployed app's domain name, as shown in the following example. Be sure to replace <API_NAME> and <default-domain-of-container-app-environment> with your actual values. For example, with the default domain for your Azure Container App environment from the previous step and ms-identity-api for your app name, you would use https://ms-identity-api.<default-domain> for the post-logout-redirect-uri value.

    post-logout-redirect-uri: https://<API_NAME>.<default-domain-of-container-app-environment>

  2. After saving this file, use the following command to rebuild your app:

    mvn clean package

Important

The application.yml file of the application currently holds the value of your client secret in the client-secret parameter. It isn't good practice to keep this value in this file. You might also be taking a risk if you commit the file to a Git repository. For the recommended approach, see Manage secrets in Azure Container Apps.

Update your Microsoft Entra ID app registration

Because the redirect URI changes to your deployed app on Azure Container Apps, you also need to change the redirect URI in your Microsoft Entra ID app registration. Use the following steps to make this change:

  1. Navigate to the Microsoft identity platform for developers App registrations page.

  2. Use the search box to search for your app registration - for example, java-servlet-webapp-authentication.

  3. Open your app registration by selecting its name.

  4. Select Authentication from the menu.

  5. In the Web - Redirect URIs section, select Add URI.

  6. Fill out the URI of your app, appending /login/oauth2/code/ - for example, https://<containerapp-name>.<default domain of container app environment>/login/oauth2/code/.

  7. Select Save.

Deploy the app

Deploy the JAR package to Azure Container Apps.

Note

If necessary, you can specify the JDK version in the Java build environment variables. For more information, see Build environment variables for Java in Azure Container Apps.

Now you can deploy your WAR file with the az containerapp up CLI command.

az containerapp up \
    --name $API_NAME \
    --resource-group $RESOURCE_GROUP \
    --location $LOCATION \
    --environment $ENVIRONMENT \
    --artifact <JAR_FILE_PATH_AND_NAME> \
    --ingress external \
    --target-port 8080 \
    --query properties.configuration.ingress.fqdn

Note

The default JDK version is 17. If you need to change the JDK version for compatibility with your application, you can use the --build-env-vars BP_JVM_VERSION=<YOUR_JDK_VERSION> argument to adjust the version number.

For more build environment variables, see Build environment variables for Java in Azure Container Apps.

Validate the app

In this example, the containerapp up command includes the --query properties.configuration.ingress.fqdn argument, which returns the fully qualified domain name (FQDN), also known as the app's URL. Use the following steps to check the app's logs to investigate any deployment issue:

  1. Access the output application URL from the Outputs page of the Deployment section.

  2. From the navigation pane of the Azure Container Apps instance Overview page, select Logs to check the app's logs.

Explore the sample

Use the following steps to explore the sample:

  1. Notice the signed-in or signed-out status displayed at the center of the screen.
  2. Select the context-sensitive button in the corner. This button reads Sign In when you first run the app. Alternatively, select token details. Because this page is protected and requires authentication, you're automatically redirected to the sign-in page.
  3. On the next page, follow the instructions and sign in with an account in the Microsoft Entra ID tenant.
  4. On the consent screen, notice the scopes that are being requested.
  5. Upon successful completion of the sign-in flow, you should be redirected to the home page - which shows the sign in status - or the token details page, depending on which button triggered your sign-in flow.
  6. Notice that the context-sensitive button now says Sign out and displays your user name.
  7. If you're on the home page, select ID Token Details to see some of the ID token's decoded claims.
  8. Use the button in the corner to sign out. The status page reflects the new state.

About the code

This sample demonstrates how to use Microsoft Entra ID Spring Boot Starter client library for Java to sign in users into your Microsoft Entra ID tenant. The sample also makes use of the Spring Oauth2 Client and Spring Web boot starters. The sample uses claims from the ID token obtained from Microsoft Entra ID to display the details of the signed-in user.

Contents

The following table shows the contents of the sample project folder:

File/folder Description
pom.xml Application dependencies.
src/main/resources/templates/ Thymeleaf Templates for UI.
src/main/resources/application.yml Application and Microsoft Entra ID Boot Starter Library Configuration.
src/main/java/com/microsoft/azuresamples/msal4j/msidentityspringbootwebapp/ This directory contains the main application entry point, controller, and config classes.
.../MsIdentitySpringBootWebappApplication.java Main class.
.../SampleController.java Controller with endpoint mappings.
.../SecurityConfig.java Security configuration - for example, which routes require authentication.
.../Utilities.java Utility class - for example, filter ID token claims.
CHANGELOG.md List of changes to the sample.
CONTRIBUTING.md Guidelines for contributing to the sample.
LICENSE The license for the sample.

ID token claims

To extract token details, the app makes use of Spring Security's AuthenticationPrincipal and OidcUser object in a request mapping, as shown in the following example. See the Sample Controller for the full details of how this app makes use of ID token claims.

import org.springframework.security.oauth2.core.oidc.user.OidcUser;
import org.springframework.security.core.annotation.AuthenticationPrincipal;
//...
@GetMapping(path = "/some_path")
public String tokenDetails(@AuthenticationPrincipal OidcUser principal) {
    Map<String, Object> claims = principal.getIdToken().getClaims();
}

For sign-in, the app makes a request to the Microsoft Entra ID sign-in endpoint automatically configured by Microsoft Entra ID Spring Boot Starter client library for Java, as shown in the following example:

<a class="btn btn-success" href="/oauth2/authorization/azure">Sign In</a>

For sign-out, the app makes a POST request to the logout endpoint, as shown in the following example:

<form action="#" th:action="@{/logout}" method="post">
  <input class="btn btn-warning" type="submit" value="Sign Out" />
</form>

Authentication-dependent UI elements

The app has some simple logic in the UI template pages for determining content to display based on whether the user is authenticated, as shown in the following example using Spring Security Thymeleaf tags:

<div sec:authorize="isAuthenticated()">
  this content only shows to authenticated users
</div>
<div sec:authorize="isAnonymous()">
  this content only shows to not-authenticated users
</div>

Protect routes with AADWebSecurityConfigurerAdapter

By default, the app protects the ID Token Details page so that only signed-in users can access it. The app configures these routes by using the app.protect.authenticated property from the application.yml file. To configure your app's specific requirements, apply the AadWebApplicationHttpSecurityConfigurer#aadWebApplication method to the HttpSecurity instance. For an example, see this app's SecurityConfig class, shown in the following code:

@Configuration
@EnableWebSecurity
@EnableMethodSecurity
public class SecurityConfig  {
    
    @Value("${app.protect.authenticated}")
    private String[] allowedOrigins;
    
    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        // @formatter:off
        http.apply(AadWebApplicationHttpSecurityConfigurer.aadWebApplication())
            .and()
            .authorizeHttpRequests(auth -> auth
                .requestMatchers(allowedOrigins).authenticated()
                .anyRequest().permitAll()
                );
        // @formatter:on
        return http.build();
    }

    @Bean
    @RequestScope
    public ServletUriComponentsBuilder urlBuilder() {
        return ServletUriComponentsBuilder.fromCurrentRequest();
    }    
}

More information

For more information about how OAuth 2.0 protocols work in this scenario and other scenarios, see Authentication Scenarios for Microsoft Entra ID.