Using the @Value annotation in Spring Boot
problem
You want to use a value from a properties file to load into a field in your class. In this post we will see how to do that using Spring boot.
SOLUTION
Using the @Value annotation. We can place this annotation on a field, e.g. String. Let’s say we wish to load a default message from our application.properties to one of our fields.
message="A default message"
Simply we use that annotation, e.g on a field to load the value into it:
@Value("${message}")
private String message;
running
Let’s create a complete Rest Controller and retrieve the value from the frontend.
package com.programmerabroad.value;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
public class ValueApplication {
@Value("${message}")
private String message;
public static void main(String[] args) {
SpringApplication.run(ValueApplication.class, args);
}
@GetMapping("/")
public String index() {
return message;
}
}
We open our browser on the default url that Spring boot runs: http://localhost:8080/
output
conclusion
In this post we saw how to use the @Value annotation on a field and load a String message from the application.properties file into a class field and subsequently print it to the Http response body.
Reference:
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Ellion
Professional IT consultant, writer, programmer enthusiast interested in all sorts of coding.
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