Spring @PropertySource annotation tutorial
last modified October 18, 2023
Spring @PropertySource annotation tutorial shows how to use @PropertySource annotation to include properties into the Environment and inject properties with @Value.
Spring is a popular Java application framework for creating enterprise applications.
Spring @PropertySource
@PropertySource is a convenient annotation for including PropertySource
to Spring's Environment and allowing to inject properties via @Value into class
attributes. (PropertySource is an object representing a set of property pairs
from a particular source.)
@PropertySource is used together with @Configuration.
Spring @PropertySource example
The application uses Spring's @PropertySource to include properties from
the application.properties file into the Environment and to inject them
into class attributes.
pom.xml
src
├───main
│ ├───java
│ │ └───com
│ │ └───zetcode
│ │ │ Application.java
│ │ └───config
│ │ AppConfig.java
│ └───resources
│ application.properties
│ logback.xml
└───test
└───java
This is the project structure.
<?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
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.zetcode</groupId>
<artifactId>propertysource</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
<spring-version>5.3.23</spring-version>
</properties>
<dependencies>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.4.0</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring-version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring-version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<mainClass>com.zetcode.Application</mainClass>
</configuration>
</plugin>
</plugins>
</build>
</project>
In the pom.xml file, we have basic Spring dependencies spring-core,
spring-context, and logging logback-classic dependency.
The exec-maven-plugin is used for executing Spring application from the
Maven on the command line.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<logger name="org.springframework" level="ERROR"/>
<logger name="com.zetcode" level="INFO"/>
<appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n
</Pattern>
</encoder>
</appender>
<root>
<level value="INFO" />
<appender-ref ref="consoleAppender" />
</root>
</configuration>
The logback.xml is a configuration file for the Logback logging library.
app.name=My application app.version=1.1
We have two properties in application.properties file.
package com.zetcode.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
@Configuration
@PropertySource(value = "application.properties", ignoreResourceNotFound = true)
public class AppConfig {
}
AppConfig is the application configuration class. The @PropertySource
injects properties from the application.properties into the Spring's Environment.
package com.zetcode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.core.env.Environment;
@ComponentScan(basePackages = "com.zetcode")
public class Application {
private static final Logger logger = LoggerFactory.getLogger(Application.class);
@Autowired
private Environment env;
@Value("${app.name}")
private String appName;
@Value("${app.version}")
private String appVersion;
public static void main(String[] args) {
var ctx = new AnnotationConfigApplicationContext(Application.class);
var app = ctx.getBean(Application.class);
app.run();
ctx.close();
}
private void run() {
logger.info("From Environment");
logger.info("Application name: {}", env.getProperty("app.name"));
logger.info("Application version: {}", env.getProperty("app.version"));
logger.info("Using @Value injection");
logger.info("Application name: {}", appName);
logger.info("Application version: {}", appVersion);
}
}
In the Application, we get the properties using two methods.
@Autowired private Environment env;
We inject the Environment. We can retrieve the properties with
its getProperty method.
@Value("${app.name}")
private String appName;
@Value("${app.version}")
private String appVersion;
We inject the properties with @Value annotation into the attributes.
logger.info("From Environment");
logger.info("Application name: {}", env.getProperty("app.name"));
logger.info("Application version: {}", env.getProperty("app.version"));
The first way to retrieve properties is from the Environment using
the getProperty method.
logger.info("Using @Value injection");
logger.info("Application name: {}", appName);
logger.info("Application version: {}", appVersion);
The second way is to use the injected attributes.
$ mvn -q exec:java 15:00:20.653 INFO com.zetcode.Application - From Environment 15:00:20.668 INFO com.zetcode.Application - Application name: My application 15:00:20.668 INFO com.zetcode.Application - Application version: 1.1 15:00:20.668 INFO com.zetcode.Application - Using @Value injection 15:00:20.668 INFO com.zetcode.Application - Application name: My application 15:00:20.668 INFO com.zetcode.Application - Application version: 1.1
We run the application.
In this article we have shown how to use @PropertySource annotation to conveniently
work with properties in a Spring application.
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