Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:
Once the early-adopter seats are all used, the price will go up and stay at $33/year.
Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.
Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.
To learn more about Java features on Azure Container Apps, visit the documentation page.
You can also ask questions and leave feedback on the Azure Container Apps GitHub page.
Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.
Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.
To learn more about Java features on Azure Container Apps, you can get started over on the documentation page.
And, you can also ask questions and leave feedback on the Azure Container Apps GitHub page.
Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.
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Try a 14-Day Free Trial of Orkes Conductor today.
Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.
Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.
With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.
Try a 14-Day Free Trial of Orkes Conductor today.
Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.
Get started with mocking and improve your application tests using our Mockito guide:
Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.
Get started with understanding multi-threaded applications with our Java Concurrency guide:
Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:
Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.
But these can also be overused and fall into some common pitfalls.
To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:
Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:
Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.
I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.
You can explore the course here:
All Access is finally out, with all of my Spring courses. Learn JUnit is out as well, and Learn Maven is coming fast. And, of course, quite a bit more affordable. Finally.
>> GET THE COURSE
Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.
Get started with Spring Data JPA through the guided reference course:
End-to-end testing is a very useful method to make sure that your application works as intended. This highlights issues in the overall functionality of the software, that the unit and integration test stages may miss.
Playwright is an easy-to-use, but powerful tool that automates end-to-end testing, and supports all modern browsers and platforms.
When coupled with LambdaTest (an AI-powered cloud-based test execution platform) it can be further scaled to run the Playwright scripts in parallel across 3000+ browser and device combinations:
Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:
Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:
1. Overview
In this quick tutorial, we’ll learn how to inject a map from a YAML file in Spring Boot.
First, we’ll start with a little bit of insight on YAML files in Spring Framework. Then we’ll demonstrate how to bind YAML properties to a Map with a practical example.
2. YAML Files in Spring Framework
Using YAML files to store external configuration data is a common practice among Spring developers. Basically, Spring supports YAML documents as an alternative to properties, and uses SnakeYAML under the hood to parse them.
Without further ado, let’s see what a typical YAML file looks like:
server:
port: 8090
application:
name: myapplication
url: http://myapplication.comAs we can see, the YAML file is self-explanatory and more human-readable. As a matter of fact, YAML provides a fancy and concise way to store hierarchical configuration data.
By default, Spring Boot reads configuration properties from application.properties or application.yml at application startup. However, we can use @PropertySource to load a custom YAML file.
Now that we’re familiar with what a YAML file is, let’s see how to inject YAML properties as a Map in Spring Boot.
3. How to Inject a Map From a YAML File
Spring Boot has taken data externalization to the next level by providing a handy annotation called @ConfigurationProperties. This annotation is introduced to easily inject external properties from configuration files directly into Java objects.
In this section, we’ll focus on how to bind YAML properties into a bean class using the @ConfigurationProperties annotation.
First, we’ll define some key-value properties in application.yml:
server:
application:
name: InjectMapFromYAML
url: http://injectmapfromyaml.dev
description: How To Inject a map from a YAML File in Spring Boot
config:
ips:
- 10.10.10.10
- 10.10.10.11
- 10.10.10.12
- 10.10.10.13
filesystem:
- /dev/root
- /dev/md2
- /dev/md4
users:
root:
username: root
password: rootpass
guest:
username: guest
password: guestpassIn this example, we’ll try to map application into a simple Map<String, String>. Similarly, we’ll inject config details as a Map<String, List<String>>, users as a Map with String keys, and objects belonging to a user-defined class (Credential) as values.
Then we’ll create a bean class, ServerProperties, to encapsulate the logic of binding our configuration properties to Maps:
@Component
@ConfigurationProperties(prefix = "server")
public class ServerProperties {
private Map<String, String> application;
private Map<String, List<String>> config;
private Map<String, Credential> users;
// getters and setters
public static class Credential {
private String username;
private String password;
// getters and setters
}
}As we can see, we decorated the ServerProperties class with @ConfigurationProperties. That way, we tell Spring to map all the properties with the specified prefix to an object of ServerProperties.
Recall that our app needs to be enabled for configuration properties as well, though this is done automatically in most Spring Boot applications.
Finally, we’ll test if our YAML properties are properly injected as Maps:
@RunWith(SpringRunner.class)
@SpringBootTest
class MapFromYamlIntegrationTest {
@Autowired
private ServerProperties serverProperties;
@Test
public void whenYamlFileProvidedThenInjectSimpleMap() {
assertThat(serverProperties.getApplication())
.containsOnlyKeys("name", "url", "description");
assertThat(serverProperties.getApplication()
.get("name")).isEqualTo("InjectMapFromYAML");
}
@Test
public void whenYamlFileProvidedThenInjectComplexMap() {
assertThat(serverProperties.getConfig()).hasSize(2);
assertThat(serverProperties.getConfig()
.get("ips")
.get(0)).isEqualTo("10.10.10.10");
assertThat(serverProperties.getUsers()
.get("root")
.getUsername()).isEqualTo("root");
}
}4. @ConfigurationProperties vs @Value
Now let’s do a quick comparison of @ConfigurationProperties and @Value.
Despite the fact that both annotations can be used to inject properties from configuration files, they are quite different. The major difference between these two annotations is that each one serves a different purpose.
In short, @Value allows us to directly inject a particular property value by its key. However, @ConfigurationProperties annotation binds multiple properties to a particular object, and provides access to the properties through the mapped object.
In general, Spring recommends using @ConfigurationProperties over @Value when it comes to injecting configuration data. @ConfigurationProperties offers a great way to centralize and group configuration properties in a structured object that we can inject later into other beans.
5. Conclusion
In this brief article, we discussed how to inject a Map from a YAML file in Spring Boot. Then we highlighted the difference between @ConfigurationProperties and @Value.
The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.
