Web Application in Java using Three Layered Architecture Project

Web Application in Java using Three Layered Architecture

Project report submitted in partial fulfilment of the requirement for the

degree of Bachelor of Technology

Computer Science and Engineering

PARUL SHARMA (191206)

UNDER THE SUPERVISION OF

Dr EKTA GANDOTRA

Department of Computer Science & Engineering and Information

Technology

Jaypee University of Information Technology, Waknaghat, 173234,

Himachal Pradesh, INDIA

CERTIFICATE

Candidate’s Declaration

I hereby declare that the work presented in this report entitled Web Application in Java using

three-layered structure in partial fulfilment of the requirements for the award of the degree of

Bachelor of Technology in Computer Science and Engineering submitted in the Department

of Computer Science and Engineering, the Jaypee University of Information Technology

Waknaghat is an authentic record of my own work carried out over a period from July 2022 to

May 2023 under the supervision of Dr Ekta Gandotra (Associate Professor, Department of

Computer Science & Engineering and Information Technology).

I also authenticate that I have carried out the above-mentioned project work under the

proficiency stream data science.

The matter embodied in the report has not been submitted for the award of any other degree or

diploma.

Parul Sharma,191206

This is to certify that the above statement made by the candidate is true to the best of my

knowledge.

Dr Ekta Gandotra

Associate Professor

Department of Computer Science & Engineering and Information Technology

PLAGIARISM CERTIFICATE

ACKNOWLEDGEMENT

Firstly, I express our heartiest thanks and gratefulness to almighty God for his divine blessing

to make it possible to complete the project work successfully. I am grateful and wish my

profound indebtedness to Supervisor Dr Ekta Gandotra, Associate Professor, Department

of CSE Jaypee University of Information Technology, Wakhnaghat. The deep knowledge &

keen interest of my supervisor in the field of computer science helped me to carry out this

project. Her endless patience, scholarly guidance, continual encouragement, constant and

energetic supervision, constructive criticism, valuable advice, and reading many inferior

drafts and correcting them at all stages have made it possible to complete this project.

I would like to express my heartiest gratitude to Dr Ekta Gandotra, Department of CSE,

for her kind help to finish my project.

I would also generously welcome each one of those individuals who have helped me

straightforwardly or in a roundabout way in making this project a win. In this unique

situation, I want to thank the various staff individuals, both educating and non-instructing,

which have developed their convenient help and facilitated our undertaking.

Finally, I must acknowledge with due respect the constant support and patience of my parents.

Parul Sharma (191206)

III

TABLE OF CONTENT

Content Page No.

Certificate…………..…..…………………………………………………………………….. I

Plagiarism Certificate……………………………………………..……………………...…...II

Acknowledgment…………………………………………………..……………………...…III

Table of Content………………………………………………….………………...………...IV

List of Figures………………………………………………………………………………...VI

List of Tables…………………………………………………………………………..……VIII

Abstract……………………………………………………………………………………….IX

Chapter 01: INTRODUCTION 1

1.1 Introduction…………………………………………………………………………….….1

1.1.1 Job description…………………………………………………………………….…1

1.1.2 Company……………………………………………………………………………..2

1.1.3 Java programming language…………………………………...…………………....3

1.2 Problem Statement…………………………………………………………..………….….3

1.3 Objectives………………………………………………………………………..….…..….3

1.4 Motivation………………………………………………………………………..….…..…3

1.5 Methodology.………..………………………………………………………….…..…..….4

1.6 Organisation………………………………………………………………………….…….5

Chapter 02: LITERATURE SURVEY 6

Chapter 03: SYSTEM DEVELOPMENT 11

3.1 Libraries/Frameworks used……………………………………………………………....11

3.2 Technical Requirements……………………………………………………………….....12

3.2.1 Hardware Configuration………………………………..……………………...12

3.2.2 Software Configuration………………………………….……………….…….13

3.3 Model Development……………………………………………………………..….…….14

3.3.1 Algorithm…………………………………………………………….……………15

3.3.2 Deployment…………………………………………………………….………….16

Chapter 04: Experiments and Results Analysis 18

4.1 API Requests………………………………………………………………………..…....18

4.2 Exception Handling...…………………………………………………………..……..….20

4.3 Swagger…………………………………………………………………………….…….21

4.4 Deployment on AWS…………………………………………………………………….29

4.5 Unit Testing………………………………………………………………………………30

Chapter 05: CONCLUSION 33

5.1 Conclusion………………………………………………………………………………..32

5.2 Future Scope……………………………………………………………………………...32

5.2 Applications Contributions……………………………………………………………….33

REFERENCES 35

LIST OF FIGURES

Figure No.

Title

Page No.

Figure 1

Software Development Cycle

Figure 2

Zopsmart Logo

Figure 3

Spring Boot Application Methodology

Figure 4

IntelliJ Idea

Figure 5

PostgreSQL Logo

Figure 6

Docker Desktop

Figure 7

Get Request

Figure 8

Post Request

Figure 9

Patch Request

Figure 10

Exception Handling

Figure 11

Swagger

Figure 12

Create Category (Post Request)

Figure 13

Output For Create Category

Figure 14

Edge Case (Category name is null for creating

category)

Figure 15

Output Edge Case (Category name is null for

creating category)

Figure 16

Get All Categories (Get Request)

Figure 17

Create Product (Post Request)

Figure 18

Output Create Product (Post Request)

Figure 19

Edge Case Create Product (Product name is

null)

Figure 20

Output Edge Case Create Product (Product

name is null)

Figure 21

Get All Products (Get Request)

Figure 22

Update Product (Patch Request)

Figure 23

Edge Case Update Product (Product id does

not exist)

Figure 24

Edge Case Update Product (Category id does

not exist)

Figure 25

Update Product (Patch Request)

Figure 26

Edge Case Get Product (Category id does not

exist)

Figure 27

AWS deployment

Figure 28

Test for Category Controller Class

Figure 29

Test for Product Controller Class

Figure 30

Test for Category Service Class

Figure 31

Test for Product Service Class

Figure 32

Test Coverage for Web Application

VII

LIST OF TABLES

Table No.

Title

Page No.

Table 1

Comparison of Related Works

8-9

Table 2

Hardware Configuration

Table 3

Software Configuration

VIII

ABSTRACT

The process of building a web application is very straightforward, but testing, structuring,

cleaning, and maintaining the code is difficult. To address this, we use a Three Layered

Architecture in Java(SpringBoot).

The three layers are controller, service and dao/repository which are all independent of each

other. The handler/controller layer sets the API endpoints and receives the request body and

then parses anything that is required from that request. It then calls the service layer where all

the logic of the program is defined, ensures that the response is in the required format and

writes it to the response writer. This layer further communicates with the datastore/dao layer.

It takes whatever it needs from the handler layer and then calls the datastore layer. The

datastore layer is where all the data is stored. It can be any data storage. The dao layer is the

only layer that communicates with the database. That is how we test each layer(unit testing

using Mockito and JUnit) independently making sure that no layer affects the other.

Also after this, the web application was deployed using an AWS EC2 instance.

CHAPTER 1

INTRODUCTION

1.1 Introduction

An internship is a professional learning opportunity that provides an opportunity for students

to excel and improve. Students can obtain new skills while exploring and furthering their

careers through internships. My current internship at Zopsmart is described in this document.

This internship report outlines the steps that helped me achieve a number of my stated

objectives. I was given the role of Software Development Engineer Intern for my internship.

During the first few months of the internship, we were required to master the Java

programming language. I was given a live project after completing this learning procedure.

1.1.1 Job Description

In the application of engineering the goal are the making, implementation, and technical

management of software is called software engineering. Software engineering was made to

point to the problems that come with software development. When software surpasses

timelines, budgets, and quality standards, issues occur. It makes certain that the software is

created consistently, accurately, on schedule, within budget, and in accordance with the

requirements. Software engineering has grown in importance in order to keep up with the

users' continually changing needs and the environment in which the programme is anticipated

to operate.

Fig 1: Software development cycle

Assisting with software design and development is the responsibility of the Software Engineer

Trainee. They work together with other members of the team to develop secure and reliable

software. Application development (code, programming), code debugging, and testing are the

activities and responsibilities of this role. New software programmes, as well as detecting and

addressing a variety of technical issues. Partnering with senior executives to identify issues

and propose solutions.

1.1.2 Company

Modern retail technology provider ZopSmart offers all the resources needed to launch an

online store. ZopSmart provides a set of tools that can help you get there quickly and

effectively whether you're a conventional store trying to develop an omnichannel business or

an online-only shop looking to grow an e-commerce business. E-commerce has been

increasingly popular over time. And it is clear that the market for online stores offers a variety

of possibilities. Let's say you're a shop looking to launch your own online business. ZopSmart

can help companies create a strong foundation for their online growth using the many

technologies at their disposal. Many suppliers can use the goods that ZopSmart offers to start

their own online retail businesses. Additionally, there are several ways to make the experience

better, such as installing a self-checkout system. According to the NRF 2020 consumer

survey, more than 83% of shoppers believe convenience is more essential now than it was five

years ago. Before we even understood what the phrase "coronavirus" meant, this survey was

done in October 2019. Since shutdowns and social isolation have become the norm,

convenience is no longer a "nice to have," but rather a "must have" quality. Online usage of

Covid-19 has increased, and according to recent NRF polls, demand will increase even after

the bulk of the population has received the vaccine.

Fig 2: Zopsmart Logo

1.1.3 Programming Language: Java

What is Java technology, and why do I need it?

Java is a computer platform for application development as well as an object-oriented,

class-based, and concurrent programming language, which implies that numerous statements

may be processed concurrently rather than sequentially. It is free to use and runs on all

platforms.

Most programming languages need you to compile or interpret a programme before running it

on your computer. The Java programming language is unique in that it compiles and interprets

programmes. The compiler initially converts a programme into an intermediate language

known as Java bytecodes, which are platform-independent codes processed by the Java

platform's interpreter. On the computer, the interpreter parses and executes each Java bytecode

command.

1.2 Problem Statement

To create a basic SpringBoot web application that implements CRUD operations on products

and categories based on the three-layered architecture. Programs at each layer have their own

unit test.

1.3 Objectives

The goal of the internship is to learn more about programming languages like Java and to

create testable, structured, clean and maintainable web applications by using industry best

practices. After the training, I was assigned to work on a real-world project i.e. Training and

Upskilling for the company. This internship provides students with hands-on experience in

order for them to gain a better understanding of the sector. The goal was to gain enough

knowledge to be able to work efficiently on the project that had been assigned to us.

1.4 Motivation

To apply industry best practices and create a fast, scalable and secure web application.

1.5 Methodology

Fig 3:Spring Boot Application Methodology

Layered Architecture

Layers are independent of each other and communicate with each other through an interface.

Basically, this helps us make our application modular, readable and maintainable.

This has 3 layers- the HTTP layer, the Service layer, and the Dao layer.

● HTTP layer/controller: validates query/path parameters, request body, and header

checks.

● Service layer: Implements business logic and communicates with the dao layer.

● Dao layer: Implements database-level queries.

Each layer communicates with its previous/next layer using an interface(methods with input

parameters and output types are defined). Testing of each layer is done by mocking its

interface/DB/Server based on necessity.

1.6 Organisation

The remainder of the report is organised as follows: The literature survey on Java and other

documentation is summarised in Chapter 2. The methodology and system development is

described in Chapter 3. The experimental results and performance analysis based on the unit

testing are shown in Chapter 4. The paper's conclusion and future scope are provided in

Chapter 5.

Chapter-2

LITERATURE SURVEY

Popular Java framework Spring Boot offers a streamlined, opinionated approach to

application development, making it easier to create web applications. We will examine the

current state of research on Spring Boot web applications and talk about the key discoveries

and contributions made in this field in this literature review.

Overview of Spring Boot Web Applications:

A web framework called Spring Boot, which is built on top of the Spring framework, aims to

make the development of web applications simpler. Spring Boot applications are simple to

build and require little configuration. The framework is well-liked by developers because it

offers a variety of features like auto-configuration, embedded web servers, and support for

different data sources.

1. Performance: Several studies have looked into how well Spring Boot web apps run.

Overall, the outcomes have been encouraging, with studies claiming that Spring Boot apps

perform on par with or even better than those built using alternative Java web frameworks.

The performance of Spring Boot, Play, and Vert. x frameworks, for instance, was examined in

a study by Xu et al. [1] and it was discovered that Spring Boot performed the best in terms of

throughput and reaction time..

2. Security: Numerous research has looked into the security of Spring Boot apps because

security is a crucial component of developing online applications. The studies have

concentrated on a number of security-related topics, including secure coding techniques,

authentication, and authorization. For instance, Baker et al.[2] examined the security flaws in

Spring Boot apps and discovered that many of them were susceptible to popular attacks like

SQL injection and cross-site scripting (XSS).

3. Development Process: Numerous research has also examined the creation of Spring Boot

web apps. The ability of Spring Boot to expedite and simplify the development process is one

of its main advantages. For instance, in research by Aris et al. [3], which created a backend

application for a public complaint system and analysed the effects of Spring Boot on the

development process, it was discovered that the time and effort needed to create web apps

was decreased. The study noted that Spring Boot simplified the implementation of a

microservices architecture.

4. Testing: Any online application's development process must include testing, and Spring

Boot has various capabilities that make testing simpler. With an emphasis on unit testing,

integration testing, and performance testing, several studies have examined the testing of

Spring Boot applications. For instance, Debnath et al. [4] study examined the usage of the

JUnit and Mockito frameworks for testing Spring Boot apps and discovered that they were

successful in locating and correcting errors.

Popular web framework Spring Boot offers a number of features that make and speed up the

creation of online applications. The performance, security, development process, and testing

of the framework have all been the focus of several studies. The research's generally

encouraging findings demonstrate Spring Boot's advantages for developing web applications.

Author(s)

Title

Year

Methodology

Drawbacks

Xu, L., Li,

M., Chen,

W., & Liu,

A Comparative

Study on

Performance of

Web Application

Frameworks for

Java. Journal of

Physics

2018

The goal of the study

was to examine the

effectiveness of Spring

Boot, Play, and Vert. x,

three Java web

application frameworks.

The authors used a

benchmarking tool to

gauge each framework's

reaction time,

throughput, and memory

use. Vert. x had the best

throughput and fastest

reaction time, according

to the data, whereas

Spring Boot used the

least memory.

The study excluded

other well-known

frameworks like

JavaServer Faces

(JSF), Struts, and

JavaServer Pages

(JSP) and only

examined three web

application

frameworks: Spring

Boot, Play, and Vert.

x. The findings might

not thus be

transferable to other

frameworks.

The authors used a

particular hardware

and software setup to

test the frameworks.

Oras Baker

Quy

Nguyen's

A Novel

Approach to

Secure

Microservice

Architecture

from OWASP

Vulnerabilities

2019

This is a guide on

utilising Spring

Framework and Spring

Security Framework to

develop security and

design in microservices

The study may

concentrate on

certain flaws or

attack patterns, which

might not be an

accurate

representation of all

possible dangers to

microservice

architectures. The

suggested method

might not be

appropriate in all

situations and might

only be relevant to

specific kinds of

microservice

architectures.

Hatma

Suryotrisong

ko, Dedy

Puji Jayanto,

Aris

Tjahyanto

Design and

Development of

Backend

Application for

Public

Complaint

Systems Using

Microservice

Spring Boot

2017

to create a web

application using the

spring-boot

microservice

architecture for a public

complaint service.

More functionalities

could be added to the

website.

Debnath, S.,

Saha, R., &

Sarkar

Empirical

Analysis of

JUnit and

Mockito

Frameworks for

Java

Applications

Testing

2019

The study showed that

unit testing for Java

applications may be

made more successful

by combining JUnit with

Mockito.

Tests took longer to

execute thanks to

Mockito. The authors

countered that the

advantages of better

code coverage and

fewer test cases

exceeded the

drawbacks of longer

execution times.

Table 1: Comparison of Related Works

Chapter-3

SYSTEM DEVELOPMENT

3.1 Libraries/Frameworks Used

Java-It was created in 1995 by Sun Microsystems, a company that is now an Oracle

subsidiary.

Java is both a platform and a programming language. Programming with Java is high-level,

reliable, object-oriented, and secure.

SpringBoot-The Spring Framework serves as the foundation for the project known as Spring

Boot. It offers a quicker and simpler way to install, set up, and execute both straightforward

and web-based applications.

Postgres-A free and open-source relational database management system that emphasises

flexibility and SQL compliance is PostgreSQL, sometimes referred to as Postgres.

Unit Testing:

Mockito-An open source Java testing framework known as Mockito was made available

under the MIT Licence. For test-driven development or behaviour-driven development, the

framework supports the generation of test double objects in automated unit tests.

JUnit- The Java programming language has a framework for unit testing called JUnit.

Test-driven programming has benefited from JUnit.

Swagger-Users may create, document, test, and consume RESTful web services with the aid

of Swagger. It is applicable to both top-down and bottom-up API development

methodologies.

MOVING FORWARD WITH JAVA

All the backend framework such as implementing HTTP request, sending a response to the

server, writing program logic etc is written in Java.

3.2 Technical Requirements

- IntelliJ An integrated development environment (IDE) for creating software written in Java,

Kotlin, Groovy, and other JVM-based languages is called IntelliJ IDEA. It is created by

JetBrains (formerly IntelliJ), and it comes in both a proprietary commercial edition and an

Apache 2 Licenced community edition. Both are applicable to the development of businesses.

Fig 4: IntelliJ Idea

- Swagger An open-source project called Swagger2 is used to provide the REST API

documentation for RESTful web services. It offers a user interface for web browser access to

our RESTful web services. You must include the following requirements in our build settings

file in order to make Swagger2 available in a Spring Boot application.

- Postgres An effective open-source object-relational database system is PostgreSQL. It has

been in active development for more than 15 years, and because of its tried-and-true design, it

enjoys a solid reputation for dependability, data integrity, and accuracy.A database system

with more than 30 years of ongoing development is PostgreSQL. Numerous data kinds, such

as numbers, texts, dates, timestamps, and binary objects are supported. Additionally,

user-defined functions and stored procedures are supported by PostgreSQL. With its

scalability, PostgreSQL is a widely-liked option for business applications as well as for online

applications. People frequently turn to PostgreSQL to handle challenging, large-scale data

processing. This is due to the fact that PostgreSQL handles unusual database conditions better

than MySQL when comparing the two databases. Compared to other database management

systems, PostgreSQL offers greater functionalities. Additionally, because PostgreSQL is

catalogue-driven in how it operates, it is extendable. In other words, it allows you to create

data types and index types in addition to storing information about tables and columns.

Fig 5:PostgreSQL Logo

-GitHub Version control facilitates the management and tracking of coding changes in

software projects. Version management is crucial when a software project expands.A

developer replicates a portion of the source code (also known as the repository) while

branching. The developer may then safely modify that section of the code without

jeopardising the project's overall success. The developer can then integrate that code back into

the primary source code to make it official after getting their particular portion of the code to

perform properly. Then, all of these modifications are monitored and, if necessary, may be

undone. Linus Torvalds developed the open-source version management system known as Git

in 2005.

Git is a distributed version control system, which implies that every developer's computer has

access to the whole codebase and history, making branching and merging simple. A for-profit

organisation called GitHub provides a service for hosting Git repositories on the cloud. In

essence, it makes it simpler for both individuals and teams to utilise Git for collaboration and

version control. Because of GitHub's user-friendly design, even newbie programmers may

benefit from Git. Without GitHub, utilising Git often necessitates a little more command-line

experience and technical know-how.

3.2.1 Hardware Configuration

Processor: Intel Core i5-10310U CPU

RAM:16 GB

Hard Disk: 512 GB SSD

Monitor 13’’

Mouse

Keyboard

Table 2: Hardware Configuration

3.2.2 Software Configuration

Operating System Ubuntu

Language Java

Runtime Environment JRE

Table 3: Software Configuration

3.3 Model Development

The domain model for the application must be created and defined for a Spring Boot web

application. The entities and connections that make up the business logic of the application

are represented by the domain model.

The processes for creating the model for a Spring Boot web application are listed below:

1. Identify the entities: Find the entities that make up the business logic of the

application. The entities in an e-commerce platform, for instance, may include customers,

orders, items, etc.

2. Define the relationships: Define the connections between the entities when you've

recognised them. For instance, a consumer may place several orders and each purchase may

include numerous goods.

3. Create the entity classes: Make the corresponding Java entity classes based on the

recognisable entities and the connections between them. The fields, constructors, and methods

required to represent the entities should be included in these classes.

4. Define the repository interfaces: Define the repository interfaces that will be applied

to the entity class CRUD operations. These interfaces ought to build upon Spring Data JPA's

JpaRepository interface.

5. Implement the repository interfaces: Apply Spring Data JPA to the repository

interface implementation. As a result, you will be able to use straightforward method calls to

carry out CRUD actions on the entity classes.

6. Define the service interfaces: Establish the service interfaces that will be utilised to

implement the application's business logic. These interfaces should specify the procedures to

be followed when interacting with the repositories and carrying out the required tasks.

7. Implement the service interfaces: Utilise the entity classes and repository interfaces

to implement the service interfaces. You will then be able to implement the application's

business logic.

8. Define the controller classes: Create the controller classes that will manage incoming

HTTP requests, then call the relevant service methods to carry out the required tasks.

9. Implement the controller classes: Utilise the service interfaces to implement the

controller classes. By doing so, you'll be able to manage incoming HTTP requests and deliver

the necessary answers.

3.3.1 Algorithm

➔ For Category API

1. Create a Category class and fill it with necessary parameters like id and name.

2. To perform CRUD operations on categories, create a CategoryRepository interface

that extends JpaRepositoryProduct, Long>.

3. Create a class called CategoryService to house all of the program's logic and allow it

to communicate with the CategoryRepository.

4. Create a class called CategoryController to manage incoming requests and pass them

on to CategoryService.

5. To retrieve all categories, define a method in the CategoryController.

6. In the ProductController, define a method for adding new categories.

7. Set up Spring Boot to utilise a suitable database, such as PostgreSQL.

8. Launch the application, then test the endpoints using a Postman or Swagger.

➔ For Product API

1. Create a Product class using Hibernate and populate it with pertinent fields like id,

name, and category id that are mapped from the Category Table(Many to One).

2. To support CRUD operations on products, create a ProductRepository interface that

extends JpaRepository.

3. Create a class called ProductService to house all of the program's logic and allow it to

communicate with the ProductRepository.

4. Create a class called ProductController to manage incoming requests and give them

off to the ProductService.

5. To retrieve every product, define a method in the ProductController.

6. In the ProductController, define a method for adding new products.

7. Create a product update function in the ProductController.

8. Call the service routines using the necessary logic.

9. Set up Spring Boot to utilise a suitable database, such as PostgreSQL.

10. Launch the application, then test the endpoints using a Postman or

Swagger-compatible tool.

3.3.2 Deployment

Docker:

An open platform for creating, distributing, and executing programmes is Docker. You may

divide your apps from your infrastructure with the help of Docker, allowing for rapid software

delivery. You can manage your infrastructure using Docker in the same manner that you

manage your apps. You may drastically shorten the time between developing code and

executing it in production by utilising Docker's methodology for shipping, testing, and

deploying code rapidly. The ability to bundle and operate a programme in a loosely separated

environment known as a container is provided by Docker. You may execute several containers

concurrently on a single host thanks to the isolation and security. You can execute

applications without depending on what is already installed on the host because containers are

small and come with everything you need to run them. Sharing containers while working is

simple, and you can make sure that everyone you share with receives the same container that

operates in the same way.

Fig 6: Docker Desktop

One typical method for executing and maintaining apps in a cloud environment is to deploy a

Docker container on an AWS EC2 instance. Here is a quick rundown of the phases in this

procedure:

1. Create an AWS EC2 instance: For this, the proper EC2 instance type must be

chosen, the instance must be created and configured, and the security groups and key pairs

must be set up.

2. Install Docker on the EC2 instance: A technology called Docker makes it possible

to create, transport, and operate programmes inside containers. You may either download and

manually install Docker on the EC2 instance using the package management.

3. Build the Docker container image: A Dockerfile, or script containing instructions

for constructing the Docker image, must be made. The base image must be specified, the

application code must be added, and any relevant customizations must be set up.

4. Push the Docker image to a container registry: The Docker image has to be

uploaded to a container registry before you can deploy it to the EC2 instance. Popular

container registries include Docker Hub, Amazon ECR, and Google Container Registry.

5. Pull the Docker image on the EC2 instance: You may use the Docker CLI to pull

the Docker image onto the EC2 instance after it is made accessible in the container registry.

6. Run the Docker container: The "docker run" command may then be used to launch

the Docker container on the EC2 instance while supplying any required environment variables

and port mappings.

Chapter-4

EXPERIMENTS & RESULT ANALYSIS

4.1 API Requests:

Since they are now an integral part of daily life, APIs are used in practically all of our online

activities. When a developer calls the server by adding an endpoint to a URL, an API request

is made.The points of contact where an API interacts with a different system are referred to as

API endpoints. An endpoint identifies the place from which an API may access the resources

it requires. A server must be contacted for information before an API may begin to function.

An endpoint is the channel of communication that APIs utilise to transmit a request and

describe the location of a specific resource. It is crucial in specifying the precise locations of

resources that may be accessed and in ensuring the smooth operation of any software that

interacts with it.

Different types of HTTP requests:

GET Request: Data from a server is retrieved using it. The server responds to a GET request

by returning the desired information in the response body.

Fig 7: Get Request

POST Request: In the request body of a POST request, the client delivers information that

the server can utilise to build or update resources.

Fig 8: POST Request

PUT Request: In the request body of a PUT request, the client delivers information that the

server can utilise to update the requested resource.

DELETE Request: A DELETE request instructs the server to remove the given resource

when it is made by a client.

PATCH Request: In a PATCH request, the client transmits data that the server can utilise to

change a portion of the requested resource. When only a few fields of a resource need to be

updated rather than the full resource, this is helpful.

Fig 9: Patch Request

4.2 Exception Handling:

Fig 10: Exception Handling

We have a great deal of freedom when it comes to managing exceptions thanks to the

@ExceptionHandler annotation. To begin with, all we have to do to utilise it is to annotate a

method with the @ExceptionHandler annotation, either in the controller itself or in a

@ControllerAdvice class:

4.3 Swagger

Fig 11: Swagger

Category API

Create a Category

Fig 12: Create Category (Post Request)

Fig 13: Output For Create Category

Edge Cases:

1. If the category name in the request body is empty or null.

Fig 14: Edge Case (Category name is null for creating category)

Fig 15: Output Edge Case (Category name is null for creating category)

Get All Categories

Fig 16: Get All Categories (Get Request)

Products API

Create a new product

Fig 17: Create Product (Post Request)

Fig 18: Output Create Product (Post Request)

Edge Cases:

1. If the product name in the request body is empty or null.

Fig 19: Edge Case Create Product (Product name is null)

Fig 20: Output Edge Case Create Product (Product name is null)

Get All Products

Fig 21: Get All Products (Get Request)

Update a Product

Fig 22: Update Product (Patch Request)

Edge Cases:

1. If the product id does not exist

Fig 23: Edge Case Update Product (Product id does not exist)

2. If category id does not exist

Fig 24: Edge Case Update Product (Category id does not exist)

Get Product By a Category Id

Fig 25: Update Product (Patch Request)

Edge Cases:

1. If no category Id exists

Fig 26: Edge Case Get Product (Category id does not exist)

4.4 Deployment on AWS

Fig 27: AWS deployment

4.5 Unit Testing using Mockito and Junit5

Test for Controller Class:

Fig 28: Test for Category Controller Class

Fig 29: Test for Product Controller Class

Tests for Services Class:

● Category Service

Fig 30: Test for Category Service Class

● Product Service

Fig 31: Test for Product Service Class

Test Coverage:

Fig 32: Test Coverage for web application

Testing is done using mockito and Junit 5 which increases the code coverage and is helpful in

unit testing.Also there exists two types of testing i.e. integration testing and unit testing.In this

project we focussed on unit testing only.

Chapter-5

CONCLUSIONS

5.1 Conclusion

In conclusion, the three-layered Spring Boot web application is an effective and scalable

solution to create online applications. It is simpler to maintain and adjust distinct components

of the programme without impacting the others when the application is divided into display,

service, and persistence layers. User interface is handled by the controller layer, business logic

is handled by the service layer, and data storage is handled by the repository layer. This

enhances the application. Additionally, Spring Boot offers a variety of tools and features,

such as built-in support for several databases and web technologies, dependency injection,

and auto-configuration, to streamline the development process.

In conclusion three layered architectures have increased the effectiveness of the web

applications.

5.2 Future Scope

The project or web application is monolithic ,hence we can convert it into microservices

which has many advantages like:

1. Autonomous In a microservices architecture, each service component may be created,

deployed, run, and scaled independently of the functionality of other services.

2. Specialised: Each service is designed with a distinct set of skills and a focus on a certain

issue. The service may eventually become further divided into smaller services as it scales

over time. When a system is dealing with a spike in demand, it aids teams in determining the

size of infrastructure requirements, the worth of a product, and how to maintain dependability.

3. Easy Deployment: Continuous integration and delivery are made possible by

microservices, making it simple to test out new ideas or roll back if something goes wrong.

The cheap cost of failure promotes software updates, fosters development, and shortens the

time it takes to sell new features.

In monolithic application ensure these practices:

Integration: Using messaging and APIs, a monolithic programme may be connected to

various platforms and services. Integration is more crucial than ever because of the emergence

of APIs and microservices.

Maintenance: Maintenance becomes difficult when the size of monolithic application

increases. For best results enable practices such as clean code, testing, and continuous

integration and delivery.

5.3 Applications Contributions

1. E-commerce: E-commerce websites are required to be highly scalable, and strong

security is suitable for Spring Boot web applications. Also, it requires managing high traffic

on the site, carrying out safe transactions, and delivering a flawless user experience.

2. Healthcare: Patient portals, telemedicine platforms, and electronic health records

(EHR) systems may all be created in the healthcare industry using Spring Boot web apps. The

standard of hospitals and healthcare is increased, real-time services between doctors and

patients, and secure retain patient data.

3. Finance: Banking and financial applications including online banking systems,

mobile banking apps, and investment management can be done with the help of Spring Boot

web applications in the financial sector. The application can safely manage transactions and

offer real-time data analysis services.

4. Logistics: Supply chain management systems, transportation management systems,

and warehouse management systems may all be built using Spring Boot web applications.

These systems can efficiently manage inventories, plan routes and delivery schedules, and

enable real-time tracking of shipments.

5. Social networking: Social networking systems for social media, online communities,

and collaboration may be created with Spring Boot web applications.

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