Categorie: Programming

  • Testing databases with Testcontainers and Liquibase

    Testcontainers make it easy to test your database integration by providing docker containers for many databases, which can be started from within your unittest. This is great, but it requires a bit of work to get started since the databases are empty. Liquibase is a tool to manage database schema changes. Combining the two is…

  • Send an email with Spring Boot and Thymeleaf

    Using Spring Boot and Thymeleaf, it’s easy to send HTML emails to your users. This post will show the configuration and logic to send an email. We won’t go into details on how to setup the template, that’s for another time. Project setup Assuming you already use Spring Boot, we need to add two dependencies…

  • Spring Boot – Load users from database

    This is the third article in a series on authentication with Spring Boot. In the first article we authenticated using social networks, and allowed any user to access our application. In the second article we used inMemoryAuthentication for users that used the login form. In essence, we hardcoded our users. This article is about adding…

  • Spring Boot login with a form

    Previously I wrote about securing your application with social login. But not everybody has a social account. In this article we’re going to add formlogin to the application. Formlogin simply means that your users can log in with a username and password. We’re going to keep it as simple as possible, with in-memory authentication. Adding…

  • Spring Boot and Oauth2 with Thymeleaf

    Spring has a good tutorial explaining how to authenticate with your application using one or more external authentication providers, like GitHub or Google. This tutorial uses a single page application with a Rest endpoint. For a personal project I didn’t want a single page application, I wanted to use Thymeleaf. During implementation I discovered a…

  • Apache HttpClient

    For a hackaton I wanted to read some files from our BitBucket server. I knew the URLs of the files, but there were some complications. First, you need to be authenticated. According to the documentation, the preferred way of authentication is HTTP Basic Authentication when authenticating over SSL. We are using an SSL connection, but…

  • Multiple Full-Screens in Java

    Working with Java’s Full-Screen Exclusive Mode is a bit different than working with AWT, Swing or JavaFX. The tutorial describes how, and why, this works. The information, however, is a bit spread out. Also, it doesn’t mention how to work with multiple full screens at the same time. Not that it’s very different from working…

  • Jackson, JAXB, OpenAPI and Spring

    Imagine that you have a service that enriches some data. The model for the data that needs to be enriched is generated from an XSD. The model for the enriching data (the wrapper) is generated from OpenAPI specs. Those two separate models need to be combined and sent out via Spring’s RestTemplate. The problem is…

  • Rich Domain vs. Structs & Services

    When joining a project, you have to work with the code that you’re given. It’s only when you start to understand the project that you can start to change the way the problems are being solved. Most projects that I’ve joined use an object oriented language, but not all projects use object oriented principles. In…

  • Java XML Api

    Who uses XML in 2021? We all use JSON these days, aren’t we? Well, it turns out XML is still being used. These code fragments could help get you up to speed when you’re new to the Java XML API. Create an empty XML document To start from scratch, you’ll need to create an empty…