How to inject property values into Spring Boot beans - spring

Question

In my spring boot application, i'am trying to inject variable's value from the config file application.properties to my java class and i'm getting a null value.
here is the configuration of my application.properties file:
myapp.username=user#user.com
myapp.password=user
here is where i call the configuration entries:
#Component
public class MyClass{
#Value("${myapp.username}")
public String username;
#Value("${myapp.password}")
public String password;
public static void main(String[] args) {
System.out.println(password);
}
}
I hope there someone how did deal with the same problem, thanks.

Answer 1

you can use this example add bean to your config like this :
#Configuration
#ComponentScan(basePackages = "youpackagebase")
#PropertySource(value = { "classpath:application.properties" })
public class AppConfig {
/*
* PropertySourcesPlaceHolderConfigurer Bean only required for #Value("{}") annotations.
* Remove this bean if you are not using #Value annotations for injecting properties.
*/
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
and in your bean :
#Component
public class NetClient {
#Value("${bigwater.api_config.url.login}")
public String url_login;
Best Regards

Answer 2

You are not even letting the Spring Boot container to boot (initialize) as you are are writing the code directly under main.
You should have an Application class as shown below to launch the Spring boot container properly, look here.
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
As far as my understanding you wanted to execute your code once the container is started, so follow the below steps:
Add the above Application class and then in your NetClient component class add a #Postconstruct method & this method will be called automatically once the bean is ready, refer the code below:
#Component
public class NetClient {
#Value("${bigwater.api_config.url.login}")
public String url_login;
#Value("${bigwater.api_config.url.ws}")
public static String url_ws;
#Value("${bigwater.api_config.username}")
public String username;
#Value("${bigwater.api_config.password}")
public String password;
#Postconstruct
public void init() {
//place all of your main(String[] args) method code here
}
//Add authentification() method here
}