DEV Community: DzifaHodey

NoSuchFileException - How to avoid it when adding resources to a Spring Boot Application

DzifaHodey — Wed, 18 May 2022 14:21:17 +0000

Have you ever tried reading resources (json files, htm templates, text files etc) in your Spring Boot project, but got a java.nio.file.NoSuchFileException?

The NoSuchFileException occurs if the file is not in the specified location. A similar exception that occurs is the FileNotFoundException.

1. Loading Files from a directory

A common approach developers use to add resources is to place the files in the src/main/resources/ directory, and then read the files from that path.
Although not the best practice, this approach works if the project is run locally. This is because the project directory is used as the current working directory during runtime.

For example, using the code below, I can read user data from a file and save the value in a string.

application.properties

filePath=src/main/resources/filename.txt

ReadUserDataFromFile.java

public class ReadUserDataFromFile {
   @Value("${filePath}")
   private String dataFilePath;

   public String readDataFile() throws IOException {
      String data = new String(Files.readAllBytes(Paths.get(filePath)));
     return data;
    }
}

The file is successfully read if it is in the src/main/resources/ directory.

Now, if the project is packaged as a JAR file, the NoSuchFileException will be thrown when trying to read the file. This happens because filename.txt is at the root folder of the JAR and it cannot be accessed using the file path.

2. Creating a Resource object

A better approach and a solution to the NoSuchFileException is to create a org.springframework.core.io.Resource object in your class and set the value to point to the file.
Example:

ReadUserDataFromFile.java

public class ReadUserDataFromFile {
   @Value("classpath:filename.txt")
   private Resource dataFile;

   public String readDataFile() throws IOException {
      String data = new String(dataFile.getInputStream().readAllBytes());
      return data;
    }
}

With this approach, the file can be read both locally and from JAR file.

Welcoming myself to the tech blogging space

DzifaHodey — Wed, 20 Apr 2022 18:09:02 +0000

I am very excited to start documenting my software development journey. My stack is mainly Java Spring Boot and Python Flask for API Development.
My posts will be centered on general software engineering practices as well as Spring Boot concepts.

Cheers to my tech journey!

Creating my first ASP.NET Core Web API

DzifaHodey — Wed, 21 Apr 2021 16:25:59 +0000

As an Electrical & Electronic Engineering graduate, I finally decided to begin a new journey in the software development world. Although I have beginner knowledge of a few programming languages, frameworks and popular software engineering practices, I would say my learning was not structured.

My first step in this new journey is to learn ASP.NET Core development, and I'm eager to see what it has to offer! In this post, I will describe my first experience with the ASP.NET Core framework using the Microsoft Docs tutorial. I have also included links to key concepts and resources.

First of all, why ASP.NET Core?

ASP.NET Core is a web development framework based on C# that supports multiple platforms such as Windows, Linux and macOS. Being an open source framework, it is very flexible to work with.
This framework features an MVC architecture; Model, View, Controller; which makes it really easy to customize web applications and test APIs (Application Programming Interfaces). APIs are gateways that enable applications communicate with each other.
As I keep working with the framework, I hope to learn more about its usefulness and advantages over other frameworks.

Now, to the process!

After installing the .NET Software Development Kit (SDK) and getting my Visual Studio Code ready with the C# extension, I was set to start.
Using the integrated terminal in Visual Studio Code, I created a new web API project. One thing I liked was that the new project came with a template that helped give a clearer understanding of how the API worked and was structured.

To develop my API, which was a to-do list tracker, I created my database model and a database context that was set up to use an in-memory database. I then scaffolded the controller to enable it respond to web API requests using CRUD (Create, Read, Update and Delete) operations quickly and asynchronously. Scaffolding is a technique used to generate code for CRUD methods to be used to GET, POST, PUT and DELETE data in the database efficiently.
I included a Data Transfer Object (DTO) model which controls the properties that are returned to the client, and prevents over-posting. Apart from security, the DTO is useful for reducing payload size.

I thoroughly enjoyed the process of creating my first .NET CORE project, and I'm looking forward to exploring its functionality even more.
In my subsequent tasks, I will be optimizing the performance of the API.
Hope you enjoyed this read.! Like and comment :).