Question

I am new to Spring and trying to inject a string with a value using the @Value("${loginpage.message}") annotation inside of a controller annotated with the @Controller annotation and the value of my string is being evaluated as the string "${loginpage.message}" and not what is inside my properties file.

Below is my controller with the string ‘message’ that I want to inject.

@Controller
public class LoginController extends BaseController {
    @Value("${loginpage.message}")
    private String message;

    @RequestMapping("/")
    public String goToLoginPage(Model model) {
        model.addAttribute("message", message);

        return "/login";
    }
}

My application context looks like this:

<context:property-placeholder location="classpath:properties/application.properties" />

<context:annotation-config />

<context:component-scan base-package="com.me.application" />

My properties file has the line:

loginpage.message=this is a test message

Spring must be picking up the value at some point because whenever I change @Value("${loginpage.message}") to a value not in the properties file like @Value("${notInPropertiesFile}"), I get an exception.

Answer 1

It seems that the question has been already asked Spring 3.0.5 doesn't evaluate @Value annotation from properties

The difference between web app root and servlet application contexts is one of the top sources of confusion in Spring, see Difference between applicationContext.xml and spring-servlet.xml in Spring Framework

From @Value javadoc :

Note that actual processing of the @Value annotation is performed by a
BeanPostProcessor

From Spring documentation:

BeanPostProcessor interfaces are scoped per-container. This is only relevant if you are using container hierarchies. If you define a BeanPostProcessor in one container, it will only do its work on the beans in that container. Beans that are defined in one container are not post-processed by a BeanPostProcessor in another container, even if both containers are part of the same hierarchy.