How to read config file (*.yaml *.properties) without spring framework

Question

I have a project but not in spring, how can I use annotation to read content in config files like *.yaml or *.properties under resource package.

Answer 1

You can use SnakeYAML without Spring.

Download the dependency:

compile group: 'org.yaml', name: 'snakeyaml', version: '1.24'

Then you can load the .yaml (or .yml) file this way:

Yaml yaml = new Yaml();
InputStream inputStream = this.getClass().getClassLoader()
                           .getResourceAsStream("youryamlfile.yaml"); //This assumes that youryamlfile.yaml is on the classpath
Map<String, Object> obj = yaml.load(inputStream);
obj.forEach((key,value) -> { System.out.println("key: " + key + " value: " + value ); });

Reference.

Edit: Upon further investigation, OP wants to know how to load properties in Spring boot. Spring boot has a built-in feature to read properties.

Let's say you have a application.properties sitting in src/main/resources, and in it there is an entry say application.name="My Spring Boot Application", then in one of your classes annotated with @Component or any of its sub-stereotype annotations, one can fetch values like this:

@Value("${application.name}")
private String applicationName;

The property in application.property file is now bound to this variable applicationName

You could also have a application.yml file and have the same property written this way

application:
  name: "My Spring Boot Application"

You will get this property value the same way like last time by annotation a filed with @Value annotation.