Generate a self-signed certificate using Keytool
Use the following command to generate a self-signed RSA certificate that can be used during development to test your application under HTTPS.
keytool -genkey -alias tomcat -storetype PKCS12 -keyalg RSA -keysize 2048 -keystore keystore.p12 -validity 7300
For production, you will want to create a certificate via a Certificate Authority. Read How to convert a web application from HTTP to HTTPS for more information on how to create a production-ready HTTPS certificate.
Modify your application.properties file
To configure Spring Boot for HTTPS, all you need to do is add the following properties to the application.properties file in /src/main/resources/application.properties.
server.port: 443 server.ssl.key-store: keystore.p12 server.ssl.key-store-password: password server.ssl.keyStoreType: PKCS12 server.ssl.keyAlias: tomcat
Now, when you run your application make sure that the “keystore.p12” file that you generated is in the same directory as your application, or you must specify the path to it in your application.properties. Note: it must be in the same directory as your deployed application (jar), not in the same directory as the application.properties file.
You will now be able to access your application from https://localhost.
Redirect HTTP to HTTPS (optional)
It may be necessary to redirect an existing HTTP request to use the new HTTPS protocol, especially if you are changing an existing application. Read How to convert a web application from HTTP to HTTPS for more information on how to do this.