06_postgres_config.md

🟢 06 - PostgreSQL Setup and Configuration

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🔧 Configuration Options

You can configure your database credentials either via environment variables (recommended) or directly in application.properties.

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⚡ Option 1: Using .env file with Dotenv (recommended)

1. Create a .env file in your project root (example .env.example):

# .env.example

# Application name
SPRING_APPLICATION_NAME=spring-boot-project

# Database configuration
DB_URL=jdbc:postgresql://localhost:5432/springbootdb
DB_USERNAME=springuser
DB_PASSWORD=springpassword

2. Create a config class to load .env variables

Place this file under src/main/java/com/example/spring_boot_project/config/DotenvInitializer.java:

package com.example.spring_boot_project.config;

import io.github.cdimascio.dotenv.Dotenv;
import io.github.cdimascio.dotenv.DotenvException;
import jakarta.annotation.PostConstruct;
import org.springframework.context.annotation.Configuration;

@Configuration
public class DotenvInitializer {
public static Dotenv dotenv;

    @PostConstruct
    public static void init(){
        try {
            dotenv = Dotenv.configure()
                    .ignoreIfMissing()
                    .load();

            System.out.println("Dotenv loaded");
        } catch (DotenvException e) {
            throw new RuntimeException(e);
        }
    }
}

This will load the .env file and make variables available via DotenvInitializer.dotenv.

3. Initialize Dotenv in your main application class

In src/main/java/com/example/spring_boot_project/SpringBootProjectApplication.java:

package com.example.spring_boot_project;

import com.example.spring_boot_project.config.DotenvInitializer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootProjectApplication {
public static void main(String[] args) {
DotenvInitializer.init();
SpringApplication.run(SpringBootProjectApplication.class, args);
}
}

4. Access environment variables anywhere in your code like:

String dbUrl = DotenvInitializer.dotenv.get("DB_URL");

You can then configure your datasource programmatically or pass these variables to Spring.

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⚡ Option 2: Using application.properties

Alternatively, configure your database connection directly in src/main/resources/application.properties:

spring.datasource.url=jdbc:postgresql://localhost:5432/springbootdb
spring.datasource.username=springuser
spring.datasource.password=springpassword
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

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