Spring Boot application.properties value not populating

The way you are performing the injection of the property will not work, because the injection is done after the constructor is called.

You need to do one of the following:

Better solution

@Component
public class MyBean {

    private final String prop;

    @Autowired
    public MyBean(@Value("${some.prop}") String prop) {
        this.prop = prop;
        System.out.println("================== " + prop + "================== ");
    }
}

Solution that will work but is less testable and slightly less readable

@Component
public class MyBean {

    @Value("${some.prop}")
    private String prop;

    public MyBean() {

    }

    @PostConstruct
    public void init() {
        System.out.println("================== " + prop + "================== ");
    }
}

Also note that is not Spring Boot specific but applies to any Spring application

The user "geoand" is right in pointing out the reasons here and giving a solution. But a better approach is to encapsulate your configuration into a separate class, say SystemContiguration java class and then inject this class into what ever services you want to use those fields.

Your current way(@grahamrb) of reading config values directly into services is error prone and would cause refactoring headaches if config setting name is changed.

This answer may or may not be applicable to your case ... Once I had a similar symptom and I double checked my code many times and all looked good but the @Value setting was still not taking effect. And then after doing File > Invalidate Cache / Restart with my IntelliJ (my IDE), the problem went away ...

This is very easy to try so may be worth a shot

Actually, For me below works fine.

@Component
public class MyBean {

   public static String prop;

   @Value("${some.prop}")
   public void setProp(String prop) {
      this.prop= prop;
   }

   public MyBean() {

   }

   @PostConstruct
   public void init() {
      System.out.println("================== " + prop + "================== ");
   }

}

Now whereever i want, just invoke

MyBean.prop

it will return value.

Using Environment class we can get application. Properties values

@Autowired,

private Environment env;

and access using

String password =env.getProperty(your property key);

Moved no argument constructor code to PostConstruct has done the trick for me. As it'll keep default bean loading workflow intact.

@Component
public class MyBean {

    @Value("${some.prop}")
    private String prop;

    @PostConstruct
    public void init() {
        System.out.println("================== " + prop + "================== ");
    }
}

follow these steps. 1:- create your configuration class like below you can see

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.beans.factory.annotation.Value;

@Configuration
public class YourConfiguration{

    // passing the key which you set in application.properties
    @Value("${some.pro}")
    private String somePro;

   // getting the value from that key which you set in application.properties
    @Bean
    public String getsomePro() {
        return somePro;
    }
}

2:- when you have a configuration class then inject in the variable from a configuration where you need.

@Component
public class YourService {

    @Autowired
    private String getsomePro;

    // now you have a value in getsomePro variable automatically.
}

If you're working in a large multi-module project, with several different application.properties files, then try adding your value to the parent project's property file.

If you are unsure which is your parent project, check your project's pom.xml file, for a <parent> tag.

This solved the issue for me.

You can use Environment Class to get data :

@Autowired
private Environment env;
String prop= env.getProperty('some.prop');

Simplest solution that solved this issue for me:

Add @PropertySource annotation to the Component/Service that needs to populate @Value field:

@Service
@PropertySource("classpath:myproperties.properties")
public class MyService {

  @Value("${some.prop}")
  private String someProperty;

  // some logic...
}

Make sure to add the properties file to the resource folder of the same module as your Service/Component.

You are getting this error because you are initializing the class with new keyword. To solve this, first you need to create the configuration class and under this class you need to create the bean of this class. When you will call it by using bean then it will work..

package ca.testing;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import java.sql.Connection;
import java.sql.DriverManager;

@Component
@PropertySource("db.properties")
public class ConnectionFactory {
    @Value("${jdbc.user}")
    private String user;
    @Value("${jdbc.password}")
    private String password;
    @Value("${jdbc.url}")
    private String url;
    Connection connection;

    public Connection getConnection(){
        try {
            connection = DriverManager.getConnection(url, user, password);
            System.out.println(connection.hashCode());
        }catch (Exception e){
            System.out.println(e);
        }
        return connection;
    }

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context= new AnnotationConfigApplicationContext(Config.class);
        ConnectionFactory connectionFactory= context.getBean(ConnectionFactory.class);
        connectionFactory.getConnection();
    }
}

My application properties are picking after i have removed key word new from different class like (new Bean())