Roy Tutorials

Introduction In this short example code I will show you how to create a new file for writing into it or if the file already exists then append to it instead of creating a new file using Java programming language. If you have a requirement that either you need to log some data into an…

Table of Contents Introduction Where is @PreAuthorize applicable? Prerequisites Project Setup MySQL Table Data Application Config Entity Classes Repository Interfaces Service Class REST Controller Class Security Config Spring Boot Main Class Testing Spring Security – PreAuthorize hasRole Source Code Introduction PreAuthorize hasRole Spring security will determine whether a user can invoke a method or not…

Table of Contents Introduction Why do you need to prettify the JSON data? Prerequisites Pretty Print JSON Source Code Introduction In this example I am going to show you how to pretty print JSON in Python programming language. The ugly JSON or one liner JSON data or string could be very difficult to read manually…

Table of Contents Introduction Wny do you need a single jar or war Prerequisites Generating Jar Generating Thin Jar Generating Fat Jar Generating War Generating Thin War Generating Fat War Source Code Introduction Generally most of the Spring Boot applications generate jar archive for deployment. Very few Spring Boot applications generate war archive for deployment…

Table of Contents Introduction Prerequisites Project Setup MySQL Table DataSource Config Entity Class Repository Interface Service Class Spring Web Controller Spring Boot Main Class UI (User Interface) Testing Multi Steps Form Source Code Introduction In this example I am going to show you how to build multisteps form using Spring Boot thymeleaf jquery. Multi steps…

Table of Contents Introduction Prerequisites Project Setup The Junit 5 Test Class Generating Test Reports Scanning Project with Sonar Source Code Introduction In this Spring Boot based application I am going to show you how to generate Junit 5 test report using SonarQube Jacoco gradle build tool. You need to generate such test reports to…

Table of Contents Introduction Prerequisites Project Setup Setup ngx-lightbox App Module Configuration Update Title App Component App HTML App Styles Testing Angular Photo Gallery Source Code Introduction In this example I am going to show you how to create photo gallery in Angular application. Photo gallery also known as image gallery or media gallery or…

Table of Contents Introduction Prerequisites Project Directory MySQL Table Database Configuration Route Configuration Model Controller Library Testing CodeIgniter 4 REST JWT Source Code Introduction In this example I will show you how to use JWT (JSON Web Token) in CodeIgniter 4 REST API for authenticating/authorizing a user when he/she is trying to access REST API….

Table of Contents Introduction Prerequisites Project Setup Detect Hidden Rows/Cells in Excel Java Code Testing Hidden Rows/Cells Source Code Introduction Here in this example I am going to show you how to detect hidden rows in excel file using Apache POI library with the help of Java program. The following data are used in the…

Table of Contents Introduction Prerequisites Project Setup Merge Cells in Excel Testing Merged Cells Source Code Introduction Here I am going to show you how to merge cells in excel sheet using Apache POI in Java programming language. In other words I will merge two or more columns from single row or multiple rows in…

Table of Contents Introduction Why do you need to pretty print JSON data? Prerequisites Pretty Print JSON Source Code Introduction Here in this example I am going to show you how to pretty print JSON in PHP program. I will use three different kind of JSON inputs to prettify them in the output. I am…

Table of Contents Introduction Prerequisites Project Setup MySQL Table Application Properties Entity Class Repository Interface Service Class REST Controller Spring Boot Main Class Testing Hazelcast Caching Java Config for Hazelcast Source Code Introduction In this tutorial I am going to show you an example on caching using hazelcast in Spring Boot REST APIs. The cache…