Developing Spring Boot SSL Secure Sample

Introduction

In this article, I am going to explain how to develop a Spring Boot Application and configure web application to run on SSL (HTTPS) with self-signed certificate. Also I am going to explain the creation of SSL cert and import.

Overview

Before moving further, let’s understand what specific terms such as SSL or TLS means.

SSL – stands for Secure Sockets Layer. It is the industry standard protocol for keeping an internet connection secure by safeguarding all sensitive data that is being sent between two systems, preventing hackers from reading and modifying any information transferred.

TLS – (Transport Layer Security) is an updated, more secure, version of SSL. It adds more features. Today, certificates provided by certificate authorities are based on TLS only. But regarding secured communication over network, the term SSL is still common as it is the old and just become popular among community.

HTTPS – (Hyper Text Transfer Protocol Secure) appears in the URL when a website is secured by an SSL certificate. It is the secured version of HTTP protocol.

Truststore and Keystore – Those are used to store SSL certificates in Java but there is little difference between them. truststore is used to store public certificates while keystore is used to store private certificates of client or server.

Create your self signed SSL certificate

To get SSL digital certificate for our application we have two options –

1. to create a self-signed certificate

2. to obtain SSL certificate from certification authority(CA) we call it CA certificate.

In this article I am going to explain creation of self-signed certificate generated by java keytool command. We need to run the keytool -genkey command from command prompt.

Here is the exact command we will use –

keytool -genkey -alias selfsigned_localhost_sslserver -keyalg RSA -keysize 2048 -validity 700 -keypass changeit -storepass changeit -keystore ssl-server.jks

Let’s understand above command –

Ø -genkey – is the keytool command to generate the certificate, actually keytool is a multipurpose and robust tool which has several options

Ø -alias selfsigned_localhost_sslserver – indicates the alias of the certificate, which is used by SSL/TLS layer

Ø -keyalg RSA -keysize 2048 -validity 700 – are self descriptive parameters indicating the crypto algorithm, keysize and certificate validity.

Ø -keypass changeit -storepass changeit – are the passwords of our truststore and keystore

Ø -keystore ssl-server.jks – is the actual keystore where the certificate and public/private key will be stored. Here we are using JKS fromat – Java Key Store, there are other formats as well for keystore.

Once we execute above command, it will ask for certain information and finally this will look like this.

That’s all we need at this point regarding certification generation. This will generate the ssl-server.jks keystore file containing our self signed certificates in the directory from where keytool command has been executed.

To view what is inside this keystore we can again use the keytool -list command as bellow.

keytool -list -keystore ssl-server.jks

Output will be something like –

Create Spring-boot project and configure SSL

Create spring boot project

Create one spring boot project using eclipse.

File à New à Spring Starter Project.

Enter name as ‘SpringBoot-SSLSample’ , group as ‘com.eai.integration’ and click on next.

Select Web, Rest Repositories, DevTools as dependencies and select 2.0.1 as Spring Boot version. Than click on finish.

Add REST endpoint

We will use one simple REST endpoint. Create a WebController calss and add following code as shown below. This will expose one rest endpoint with relative URL /secured in the server.

That’s all we need to add web contents in our application. You can add more like adding pages, images to create a fully functional web application.

/**
 * 
 */
package com.eai.integration.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author AKSHAJ
 *
 */
@RestController
public class WebController {

 @RequestMapping("/secured")
 public String sayHello() {
  return "Hello SSL Spring Boot";
 }
}

Spring boot SSL Configuration

First we need to copy the generated keystore file (ssl-server.jks) into the resources folder.

Then open the application.properties and add the below entries.

server.port=8443
server.ssl.key-alias=selfsigned_localhost_sslserver
server.ssl.key-password=changeit
server.ssl.key-store=classpath:ssl-server.jks
server.ssl.key-store-provider=SUN
server.ssl.key-store-type=JKS

That’s all we need to enable https.

Test the Application

Now it is time to do a final maven build by command mvn clean install and start the application by java -jar target\ssl-server-0.0.1-SNAPSHOT.jar command. This will start our secured application in localhost 8443 port and our end point url will be https://localhost:8443/secured.

Since our REST endpoint is exposed over GET, we can test it through browser only. Go to https://localhost:8443/secured and you will get some browser warning like certificate is not issued from trusted certificate authorities, add exception to that in browser and you will get response from HTTPS server just created by you.

Redirect HTTP requests to HTTPS

This is an optional step in case you want to redirect your HTTP traffic to HTTPS, so that the full site becomes secured. To do that in spring boot, we need to add HTTP connector at 8080 port and then we need to set redirect port 8443. So that any request in 8080 through http, it would be automatically redirected to 8443 and https.

To do that you just need to add below configuration.

 @Bean
 public EmbeddedServletContainerFactory servletContainer() {
   TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory() {
       @Override
       protected void postProcessContext(Context context) {
         SecurityConstraint securityConstraint = new SecurityConstraint();
         securityConstraint.setUserConstraint("CONFIDENTIAL");
         SecurityCollection collection = new SecurityCollection();
         collection.addPattern("/*");
         securityConstraint.addCollection(collection);
         context.addConstraint(securityConstraint);
       }
     };
    
   tomcat.addAdditionalTomcatConnectors(redirectConnector());
   return tomcat;
 }
  
 private Connector redirectConnector() {
   Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
   connector.setScheme("http");
   connector.setPort(8080);
   connector.setSecure(false);
   connector.setRedirectPort(8443);
    
   return connector;
 }

Do a final maven build by command mvn clean install and start the application. Test http://localhost:8080/secured. It would be automatically redirected to HTTPS secured URL.

Conclusion

We learned, how we can enable HTTPS in spring boot application and also we have seen how we can redirect HTTP traffic to HTTPS. We also learned to create self signed SSL certificate. We will see more articles on spring boot soon.

Download

S. No	File Name	Size	Download
1	Developing Spring Boot SSL Secure Sample.pdf	1.0 MB	Download
2	SpringBoot-SSLSample.zip	3 KB	Download

Home