无法使用application.properties设置值

Question

I'm trying a very simple code to inject a value from application.properties. The value which is setted is the property name.

What's wrong with the code?

application.properties

set.browser = ie

    public class A {

        @Value("${set.browser}")
        private String browser;

        public A(){}

        public void print(){
            System.out.println(browser);
        }
    }

    @Configuration
    public class ABean {
        @Bean
        public A getA(){
            return new A();
        }
    }

    public class AMain {
        public static void main(String[] args) {
            AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(A.class);

            A a = context.getBean(A.class);
            a.print();

        }
    }

Answer 1

First of all your application is not spring boot application - you've just instanted spring context even without component scan. Secondly beacause of lack of component scan, your ABean is never created - your context has only A bean. To fix this you can create context from ABean:

AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ABean.class);

Thirdly you didn't configured PropertySource (if your application was spring boot application, application.properties would be default property source and it wouldn't be needed):

@PropertySource("classpath:/application.properties")
@Configuration
class ABean {
  @Bean
  public A getA() {
    return new A();
  }

}