Implementing an SSL certificate in a Spring Boot application allows you to secure the communication between the application and clients over HTTPS. Here are the steps to implement an SSL certificate in a Spring Boot application:

Step 1: Acquire an SSL Certificate:

Obtain an SSL certificate from a trusted certificate authority (CA). This typically involves generating a certificate signing request (CSR) and submitting it to the CA for validation. The CA will then issue the SSL certificate, which includes a public key and information about your server or domain.

Step 2: Store the SSL Certificate:

Store the SSL certificate file (.crt) and the corresponding private key file (.key) securely on your server. Make sure these files are accessible to your Spring Boot application.

Step 3: Configure SSL in Spring Boot:

In your Spring Boot application, configure the SSL properties in the `application.properties` or `application.yml` file. Specify the paths to the SSL certificate and private key files, along with other SSL-related properties. For example:

server:
  port: 8443

  ssl:

    enabled: true

    key-store-type: PKCS12

    key-store: classpath:keystore.p12

    key-store-password: password

    key-alias: alias

 

In this example, we enable SSL, specify the keystore type as PKCS12, provide the path to the keystore file (`keystore.p12`), set the keystore password, and specify the alias for the SSL certificate.

Step 4: Configure the Embedded Web Server:

If you are using the embedded Tomcat server in Spring Boot, you may need to configure it to use the SSL certificate. Create a bean of type `WebServerFactoryCustomizer` in your Spring Boot configuration class and override the `customize` method to configure the server. For example:

import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;

import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

@Configuration

public class ServerConfig {

    @Bean

    public WebServerFactoryCustomizer<TomcatServletWebServerFactory> servletContainerCustomizer() {

        return factory -> {

            factory.addConnectorCustomizers(connector -> {

                connector.setScheme("https");

                connector.setSecure(true);

                connector.setPort(8443);

                connector.setAttribute("keyAlias", "alias");

                connector.setAttribute("keystorePass", "password");

                connector.setAttribute("keystoreFile", "classpath:keystore.p12");

                connector.setAttribute("clientAuth", "false");

            });

        };

    }

}

In this example, we set the scheme to “https”, enable secure mode, set the port to 8443, and provide the keystore attributes such as the key alias, keystore password, and keystore file path.

Step 5: Run the Application and Test:

Start your Spring Boot application, and it will now be accessible over HTTPS using the SSL certificate you configured. Access your application using the specified port (e.g., https://localhost:8443) to test the secure connection.

By following these steps, you can successfully implement an SSL certificate in a Spring Boot application, enabling secure communication over HTTPS. Remember to keep your SSL certificate and private key files secure and renew the certificate as needed to ensure continued security.