CODEWITHSUNDEEP
javaspringspring-boot
Muatik
Muatik

Reputation: 4171

ConfigurationProperties does not bind properties

I want to bind my application.properties into a class automatically by using @ConfigurationProperties annotation. First, I tried with @Value annotation and was able to inject property values into class variables. However, @ConfigurationProperties did not inject properties into values.

my application.properties:

spring.jpa.show-sql=false
my.url=my_url
my.name=muatik

application.java

package com.muatik;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;


@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        final ApplicationContext ctx = SpringApplication.run(Application.class, args);
        final ConfigBinder confs = ctx.getBean(ConfigBinder.class);
        System.out.println(confs.getUrl());
        System.out.println(confs.getName());
    }

}

ConfigBinder.java

package com.muatik;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;



@Component
@ConfigurationProperties(prefix="my")
public class ConfigBinder {

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

    private String url; // expected to be filled automatically

    public String getUrl() {
        return this.url;
    }

    public String getName() {
        return this.name;
    }
}

output:

...
2017-01-18 15:19:29.720  INFO 4153 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-01-18 15:19:29.724  INFO 4153 --- [           main] com.muatik.Application                   : Started Application in 4.212 seconds (JVM running for 4.937)
null
muatik

What is the wrong with this implementation?

edit and solution: possible duplication: Spring Boot @ConfigurationProperties not retrieving properties from Environment

I found that I missed the setters in ConfigBinder. After adding them, it works now.

Upvotes: 22

Views: 73864

Answers (3)

GreyBit
GreyBit

Reputation: 97

As of spring boot 3 you are no longer forced to use setters to achieve property binding.
If you prefer injecting your properties through the constructor, you can now do so:
(Make sure to remove the @Component annotation as described in the accepted answer and that your constructor is not annotated with @Autowired)

@ConfigurationProperties(prefix="my")
public class ConfigBinder {

    private final String name;
    private final String url;

    public ConfigBinder(String name, String url) {
        this.name = name;
        this.url = url;
    }

    public String getUrl() {
        return url;
    }

    public String getName() {
        return name;
    }
}

@SpringBootApplication
@EnableConfigurationProperties(ConfigBinder.class)
public class Application {

    public static void main(String[] args) {
        var ctx = SpringApplication.run(Application.class, args);
        final ConfigBinder confs = ctx.getBean(ConfigBinder.class);
        System.out.println(confs.getUrl());
        System.out.println(confs.getName());
    }
}

The injection works even when the constructor is private.
If you have more than one constructor, annotate the one you want to be injected with values from properties with @ConstructorBinding.

You can even go a step further and use a record instead:

@ConfigurationProperties(prefix="my")
public record ConfigBinder(String name, String url) {
}

@SpringBootApplication
@EnableConfigurationProperties(ConfigBinder.class)
public class Application {

    public static void main(String[] args) {
        var ctx = SpringApplication.run(Application.class, args);
        final ConfigBinder confs = ctx.getBean(ConfigBinder.class);
        System.out.println(confs.url());
        System.out.println(confs.name());
    }
}

Upvotes: 0

Cyva
Cyva

Reputation: 1137

The main problem is that you do not have setters. When you put setters to ConfigBuilder works fine. The ConfigBuilder must be like this

@Component
@ConfigurationProperties(prefix="my")
public class ConfigBinder {

    private String name;

    private String url;

    // Getters and Setters !!!
}

Upvotes: 11

Strelok
Strelok

Reputation: 51481

You need to remove @Component from you properties class and add setters because standard bean property binding is used by @ConfigurationProperties:

@ConfigurationProperties(prefix="my")
public class ConfigBinder {

    private String name;

    private String url; // expected to be filled automatically

    public String getUrl() {
        return this.url;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setUrl(String url) {
        this.url = url;
    }
}

And add @EnableConfigurationProperties to your main class:

@SpringBootApplication
@EnableConfigurationProperties(ConfigBinder.class)
public class Application {

    public static void main(String[] args) {
        final ApplicationContext ctx = SpringApplication.run(Application.class, args);
        final ConfigBinder confs = ctx.getBean(ConfigBinder.class);
        System.out.println(confs.getUrl());
        System.out.println(confs.getName());
    }

}

Upvotes: 19

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