Roy Tutorials

In this tutorial we will build Spring Cloud Gateway for Microservices built using Spring Boot framework. Spring Cloud Gateway aims to provide a simple, yet effective way to route to APIs and provide cross cutting concerns to them such as: security, monitoring/metrics, and resiliency. Spring Cloud Gateway aims to provide a simple, yet effective way to route to APIs. When…

Data Deletion In this tutorial I build an application using Codeigniter framework to fetch all records (for example, products) from MySQL database and display on the HTML table. I will put checkbox against each row on the table so that user will be able to select a particular row for deletion. I will also put a checkbox on the table…

Introduction In this tutorial we will see how to check or select multiple checkboxes on HTML table using jQuery. We will put checkbox against each row on the table so that user will be able to select a particular row. We will also put a checkbox on the table header and selecting this checkbox all rows on the table will…

Introduction In this tutorial I will upload and display image using Angular. In this example I will allow to upload only single image and display the uploaded image on the web page. You might have seen how to upload file using Angular, but here I am uploading and displaying the image. I am also validating the uploaded file is image…

Unique Strings/Objects In this tutorial you will see an example on how to find unique strings or objects using Java stream API. Stream API was introduced in Java 8 and I am going to show you how to use this stream API to remove duplicates from strings or objects. Java stream API has a method distinct() that removes duplicates and…

Introduction In this example we will see how to build chat application using Nodejs, express and socket.io. You can find the original demo at https://socket.io/. This chat application has the following features: Asks for nick name from participant Tracks how many participants are there in the room Tracks who joins the room Tracks who leaves the room Tracks who is…

Introduction In this tutorial we will see how to check broken links in website using Selenium web driver. Broken links are not reachable or simply do not work. A URL for the website is no longer available. A URL of the web page was moved without a redirect being added. The URL structure of a website was changed. The link…

Introduction In this tutorial I will show you how to upload image and display on the web page once it is uploaded successfully. I have seen few tutorials on file uploads using Python Flask API but here I will show you how to allow users upload image file and display it on the browser once uploaded successfully. Related Posts: Upload…

In this tutorial we will see how to create simple Angular star rating example. We post blogs, articles, news, etc. on web sites and we sometime expect people to rate our blogs, articles, news, etc. to find out the corresponding gap or issues with our write up. It helps us improve the quality of the blogs or articles. This example…

Sparse Matrix In this example you will see how to represent sparse matrix using C programming language. A sparse matrix is one where most of its elements are zero (0). For example, the following image represents a sparse matrix: