What is the proper way to store app's conf data in Java?

In Java, one common way to store app configuration data is by using properties files. Properties files are simple text files that contain key-value pairs. Here's an example of how you can read and write app configuration data using properties files in Java:

Step 1: Create a properties file (config.properties) with some sample data:

             
app.name=MyApp
app.version=1.0
app.author=John Doe

             

Step 2: Read the properties file in Java and print the values:

             java
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class AppConfig {
    public static void main(String[] args) {
        Properties properties = new Properties();
        try (FileInputStream fis = new FileInputStream("config.properties")) {
            properties.load(fis);

            String appName = properties.getProperty("app.name");
            String appVersion = properties.getProperty("app.version");
            String appAuthor = properties.getProperty("app.author");

            System.out.println("App Name: " + appName);
            System.out.println("App Version: " + appVersion);
            System.out.println("App Author: " + appAuthor);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

             

Step 3: Run the Java program. Make sure the config.properties file is in the same directory as your Java program.

Output:

             
App Name: MyApp
App Version: 1.0
App Author: John Doe

             

Step 4: Update the properties file and write new data:

             java
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

public class AppConfig {
    public static void main(String[] args) {
        Properties properties = new Properties();
        try (FileInputStream fis = new FileInputStream("config.properties")) {
            properties.load(fis);

            // Update properties
            properties.setProperty("app.version", "2.0");
            properties.setProperty("app.author", "Jane Smith");

            // Write updated properties to file
            try (FileOutputStream fos = new FileOutputStream("config.properties")) {
                properties.store(fos, "Updated config properties");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

             

Step 5: Run the Java program again to update the properties file.

Output:

             
Updated config properties

             

By following this guide, you can easily read and write app configuration data in Java using properties files.