Spring Boot reading from application.properties (2024)

In this tutorial, we will explore the how to read data from application.properties file in Spring Boot application.

We can read properties from an application properties file in the following ways.

1. @Value annotation
2. Environment Object
3. @ConfigurationProperties annotation

Create Spring Boot Project from Spring Initializer

Project Structure

Dependencies

Add web starter dependency for web controller and lombok for auto generating getters/setter methods.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.6.3</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.techgeeknext</groupId>
	<artifactId>spring-boot-read-properties</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>spring-boot-read-properties</name>
	<description>Spring Boot Read Property File</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>

	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

@ConfigurationProperties for reading properties from application.properties

Create Configuration java class to load the properties using @ConfigurationProperties annotation. Note we have used lombok @AllArgsConstructor, @NoArgsConstructor, @Data for generating constructors and for getters/setters.

package com.techgeeknext.config;

import lombok.*;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@ConfigurationProperties(prefix="spring.datasource")
@Configuration
@AllArgsConstructor
@NoArgsConstructor
@Data
public class Configurations {
    private String username;
    private String password;
    private String platform;
}

Application Properties File

Add some properties so that we can use it for reading.

spring.application.name=config-service
spring.datasource.username=techgeeknext
spring.datasource.password=root
spring.datasource.platform=mysql

Rest Controller

Create the rest controller class. In this controller class will show all the different ways to access the properties from application.properties file.

package com.techgeeknext.controller;

import com.techgeeknext.config.Configurations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

@RestController
public class TestPropertyValController {

    @Value("${spring.application.name}")
    String applicationName;


    @Autowired
    private Environment env;

    @Autowired
    private Configurations config;


    @GetMapping("/get-values")
    public Map<String, String> getAppNameVal() {
        Map<String,String> values= new HashMap();
        values.put("using @Value--",applicationName);
        values.put("using Environment--",env.getProperty("spring.application.name"));
        values.put("using @ConfigurationProperties--",config.getUsername());
        values.put("using @ConfigurationProperties 2--",config.getPassword());
        values.put("using @ConfigurationProperties 3--",config.getPlatform());

        return values;
    }

}

Test

1. Start the Spring Boot Application by running spring-boot:run or by running main class.

2. GET - To test application properties values

   Open POSTMAN, use the rest endpoint as http://localhost:8080/get-values and click on Send button.

Download Source Code

The full source code for this article can be found on below.
Download it here - Spring Boot reading from application.properties Example