@Value for property injection in Spring Boot - Mini Project: Build & Apply

Using @Value for Property Injection in Spring Boot

📖 Scenario: You are building a simple Spring Boot application that needs to read configuration values from the application.properties file. These values will be injected into your Java class using the @Value annotation.

🎯 Goal: Learn how to use the @Value annotation to inject property values from application.properties into a Spring Boot component.

📋 What You'll Learn

Create an application.properties file with specific properties

Create a Spring Boot component class

Use @Value annotation to inject property values

Add a method to return the injected values

💡 Why This Matters

🌍 Real World

Injecting configuration values like app name, version, or API keys into Spring Boot components is common in real applications.

💼 Career

Understanding @Value is essential for configuring Spring Boot apps and managing environment-specific settings.

1

Create application.properties with properties

Create an application.properties file with these exact entries:
app.name=MySpringApp
app.version=1.0.3

Spring Boot

# Create application.properties file with the properties
# Your code here

Need a hint?

Properties files use key=value format. Make sure to write exactly app.name=MySpringApp and app.version=1.0.3.

2

Create a Spring Boot component class

Create a Java class named AppInfo annotated with @Component inside package com.example.demo.

Spring Boot

app.name=MySpringApp
app.version=1.0.3

// Create class AppInfo annotated with @Component
# Your code here

Need a hint?

Use @Component annotation above the class declaration to make it a Spring bean.

3

Inject properties using @Value

Inside the AppInfo class, create two private String fields named name and version. Use @Value to inject ${app.name} into name and ${app.version} into version.

Spring Boot

app.name=MySpringApp
app.version=1.0.3

package com.example.demo;

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

@Component
public class AppInfo {
    // Add private String fields name and version with @Value injection
    # Your code here
}

Need a hint?

Use @Value("${property.key}") above each field to inject the property value.

4

Add method to return injected values

Add a public method getAppDetails() in AppInfo that returns a String combining name and version in this format: "App: MySpringApp, Version: 1.0.3".

Spring Boot

app.name=MySpringApp
app.version=1.0.3

package com.example.demo;

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

@Component
public class AppInfo {

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

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

    // Add public method getAppDetails() that returns formatted string
    # Your code here
}

Need a hint?

Concatenate the fields name and version with the text exactly as shown.