Read values from application.properties file in Spring Boot

This post will discuss how to read a value defined in the application.properties file in a Spring Boot application.

In Spring Boot, we can use properties files, YAML files, environment variables, and command-line arguments to externalize our configuration. This is useful while working with the same application code in different environments. This post will discuss how to read a value defined in the properties files.

1. @Value annotation

The simplest way is to use the @Value annotation to load variables from the application.properties.

Suppose in application.properties, we have a property project.name. Then the property values can be injected directly into your beans by using the @Value annotation, as shown below:

import org.springframework.beans.factory.annotation.Value;

import org.springframework.stereotype.Component;

@Component

public class ProjectDetails {

@Value("${project.name}")

private String projectName;

public String getProjectName() {

return projectName;

}

public void setProjectName(String projectName) {

this.projectName = projectName;

}

Controller Code:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class Controller {

@Autowired

public ProjectDetails bean;

@RequestMapping("projectName")

String getProjectName() {

return bean.getProjectName();

}

2. Spring’s Environment abstraction

The property values can also be accessed through Spring’s Environment abstraction, as shown in the following example:

import org.springframework.context.EnvironmentAware;

import org.springframework.core.env.Environment;

import org.springframework.stereotype.Component;

@Component

public class ProjectDetails implements EnvironmentAware {

private String projectName;

@Override

public void setEnvironment(Environment environment) {

this.projectName = environment.getProperty("project.name");

}

public String getProjectName() {

return projectName;

}

public void setProjectName(String projectName) {

this.projectName = projectName;

}

Another alternative is to simply inject Environment into our controller/bean.

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.env.Environment;

import org.springframework.stereotype.Component;

@Component

public class ProjectDetails {

@Autowired

private Environment environment;

public String getProjectName() {

return environment.getProperty("project.name");

}

That’s all about reading values from the application.properties file in Spring Boot.

Read values from application.properties file in Spring Boot

1. @Value annotation

2. Spring’s Environment abstraction

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