Spring boot: place holders in properties file

You can refer the properties by using their name. See the below example.

application.properties

app.name=MyApp
app.version=1.5
app.description=${app.name} : ${app.version} is running using spring boot application

As you see, I am referring ‘app.name’ and ‘app.version’ in ‘app.description’ property.

ConfigBean.java

package com.sample.myApp.model;

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

@Component
public class ConfigBean {

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

 @Value("${app.version}")
 private String appVersion;

 @Value("${app.description}")
 private String appDescription;

 public String getAppName() {
  return appName;
 }

 public void setAppName(String appName) {
  this.appName = appName;
 }

 public String getAppVersion() {
  return appVersion;
 }

 public void setAppVersion(String appVersion) {
  this.appVersion = appVersion;
 }

 public String getAppDescription() {
  return appDescription;
 }

 public void setAppDescription(String appDescription) {
  this.appDescription = appDescription;
 }

}

Application.java

package com.sample.myApp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import com.sample.myApp.model.ConfigBean;

@SpringBootApplication
public class Application {

 public static void main(String[] args) {
  ConfigurableApplicationContext applicationContext = SpringApplication.run(Application.class, args);

  ConfigBean configBean = applicationContext.getBean(ConfigBean.class);

  String applicationName = configBean.getAppName();
  String applicationVersion = configBean.getAppVersion();
  String applicationDescription = configBean.getAppDescription();

  System.out.println("**********************************************");
  System.out.printf("Application Name : %s\n", applicationName);
  System.out.printf("Application Version : %s\n", applicationVersion);
  System.out.printf("Application Description : %s\n", applicationDescription);
  System.out.println("**********************************************");
  
  applicationContext.close();

 }

}

When you ran ‘Application.java’, you can able to see below messages in the console.

**********************************************
Application Name : MyApp
Application Version : 1.5
Application Description : MyApp : 1.5 is running using spring boot application
**********************************************

Project structure looks like below.

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