Saturday, 4 August 2018

Spring boot: Configure bean from application environment properties

You can configure a bean from application properties(application.properties) file.

Example
@ConfigurationProperties(prefix = "alpha")
@Bean
public Service alphaService() {
         return new Service();
}

Above statements populate the Service bean based on the properties prefixed with ‘alpha’.

Find the below working application.

application.properties
beta.appName="ChatServer_beta"
beta.appVersion="1.5Beta"
beta.servers[0].serverIp="5.6.7.8"
beta.servers[0].serverEnvironemnt="Testing"
beta.servers[1].serverIp="1.2.3.4"
beta.servers[1].serverEnvironemnt="Development"

alpha.appName="ChatServer_alpha"
alpha.appVersion="1.5alpha"
alpha.servers[0].serverIp="15.16.17.18"
alpha.servers[0].serverEnvironemnt="Testing"
alpha.servers[1].serverIp="11.21.31.41"
alpha.servers[1].serverEnvironemnt="Development"

Server.java

package com.sample.myApp.model;

public class Server {
 private String serverIp;
 private String serverEnvironemnt;

 public String getServerIp() {
  return serverIp;
 }

 public void setServerIp(String serverIp) {
  this.serverIp = serverIp;
 }

 public String getServerEnvironemnt() {
  return serverEnvironemnt;
 }

 public void setServerEnvironemnt(String serverEnvironemnt) {
  this.serverEnvironemnt = serverEnvironemnt;
 }

}

Service.java
package com.sample.myApp.model;

import java.util.List;

public class Service {
 private String appName;
 private String appVersion;
 private List<Server> servers;

 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 List<Server> getServers() {
  return servers;
 }

 public void setServers(List<Server> servers) {
  this.servers = servers;
 }

}


MyConfiguration.java

package com.sample.myApp.model;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyConfiguration {

 @ConfigurationProperties(prefix = "alpha")
 @Bean
 public Service alphaService() {
  return new Service();
 }
 
 @ConfigurationProperties(prefix = "beta")
 @Bean
 public Service betaService() {
  return new Service();
 }
}

Application.java

package com.sample.myApp;

import java.util.List;

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

import com.sample.myApp.model.MyConfiguration;
import com.sample.myApp.model.Server;
import com.sample.myApp.model.Service;

@SpringBootApplication
public class Application {

 private static void printServiceInfo(Service service) {
  String appName = service.getAppName();
  String appVersion = service.getAppVersion();

  System.out.println("*******************************************");
  System.out.printf("Application Name : %s\n", appName);
  System.out.printf("Application Version %s\n", appVersion);

  System.out.println("Servers Information");

  List<Server> servers = service.getServers();

  for (Server server : servers) {
   System.out.printf("Environment : %s\n", server.getServerEnvironemnt());
   System.out.printf("Server Ip : %s\n", server.getServerIp());
  }

  System.out.println("*******************************************\n\n");
 }

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

  MyConfiguration myConfiguration = applicationContext.getBean(MyConfiguration.class);
  printServiceInfo(myConfiguration.alphaService());
  printServiceInfo(myConfiguration.betaService());

  applicationContext.close();

 }

}

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


*******************************************
Application Name : "ChatServer_alpha"
Application Version "1.5alpha"
Servers Information
Environment : "Testing"
Server Ip : "15.16.17.18"
Environment : "Development"
Server Ip : "11.21.31.41"
*******************************************


*******************************************
Application Name : "ChatServer_beta"
Application Version "1.5Beta"
Servers Information
Environment : "Testing"
Server Ip : "5.6.7.8"
Environment : "Development"
Server Ip : "1.2.3.4"
*******************************************



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