ReactJS Axios GET Request Example

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In this tutorial, we'll learn how to build a React application that consumes a Spring Boot REST API using the Axios HTTP library. We'll also use Bootstrap 4 to style the UI.

Axios is a modern and Promise-based JavaScript HTTP client library that can be used both in the browser and the server with Node.js. Axios works asynchronously and allows you to make HTTP calls to REST endpoints and consume JSON REST APIs.

What we will build?

We will build a simple "single page application" using React as frontend and spring boot as backend.
We will create two projects:
1. Spring boot project - To develop simple REST API
2. React App - To consume REST API using Axios library.

Prerequisites

You will need the following prerequisites to successfully complete the steps in this tutorial:
  • JavaScript fundamentals
  • Basic understanding of REST APIs
  • Node and NPM installed on your machine

Axios Library Overview

Axios is a modern and Promise-based JavaScript HTTP client library that can be used both in the browser and the server with Node.js. Axios works asynchronously and allows you to make HTTP calls to REST endpoints and consume JSON REST APIs.

FEATURES OF AXIOS

  • Request and response interception
  • Streamlined error handling
  • Protection against XSRF
  • Support for upload progress
  • Response timeout
  • The ability to cancel requests
  • Support for older browsers
  • Automatic JSON data transformation
  • MAKING REQUESTS WITH AXIOS
Making HTTP Requests with Axios is quite easy. The code below is basically how to make an HTTP request.
// Make a GET request
axios({
  method: 'get',
  url: 'https://api.github.com/users/DemoUser',
});

// Make a Post Request
axios({
  method: 'post',
  url: '/login',
  data: {
    firstName: 'demo',
    lastName: 'user'
  }
});
The code above shows the basic ways we can make a GET and POST HTTP request with Axios.
Axios also provides a set of shorthand methods for performing different HTTP requests. Methods are as follows:
axios.request(config)
axios.get(url[, config])
axios.delete(url[, config])
axios.head(url[, config])
axios.options(url[, config])
axios.post(url[, data[, config]])
axios.put(url[, data[, config]])
axios.patch(url[, data[, config]])
In this example, we will make a GET HTTP request using the Axios library.
Learn more about how to make GET, POST, PUT and DELETE HTTP calls using Axios library at https://www.javaguides.net/2020/07/react-js-crud-application-example.html

Develop Spring Boot Backend Application

Let's first create a simple /books rest endpoint using Spring boot.

1. Create Spring Boot Project in Eclipse STS IDE

Use below guide to create Spring boot project in Eclipse STS IDE:

2. Add maven dependencies

<?xml version="1.0" encoding="UTF-8"?>
<project
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/>
        <!-- lookup parent from repository -->
    </parent>
    <groupId>net.javaguides</groupId>
    <artifactId>springboot-reactjs-example</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-reactjs-example</name>
    <description>Demo project for Spring Boot and React JS</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

3. Create Simple REST API - /books

Let's create a BookController class and add the following code to it:
package net.javaguides.springboot;

import java.util.Arrays;
import java.util.List;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class BookController {

    @CrossOrigin(origins = "http://localhost:3000")
    @GetMapping("/books")
    public List < Book > getBooks() {
        return Arrays.asList(new Book(1, "Core Java"), new Book(2, "Effective Java"), new Book(3, "Head First Java"));
    }
}

class Book {
    private int id;
    private String bookName;

    public Book(int id, String bookName) {
        super();
        this.id = id;
        this.bookName = bookName;
    }

    public int getId() {
        return id;
    }

    public String getBookName() {
        return bookName;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
}

4. Run Spring Boot Application and Test Rest API

Let's run this spring boot application from IDE -> Right-click -> Run As -> Java Application:
package net.javaguides.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringbootReactjsExampleApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootReactjsExampleApplication.class, args);
    }
}
Hit this "http://localhost:8080/books" link in a browser will display a list of books in JSON format.

Develop React JS Frontend Application

Let's go ahead and create a React application to consume below endpoint:
We are going to use browser built-in fetch() function to make a REST API call in React App.
Let's start with creating a React App using create-react-app CLI.

1 - Create a React UI with Create React App

The Create React App CLI tool is an officially supported way to create single-page React applications. It offers a modern build setup with no configuration.
To create a new app, you may choose one of the following methods:

Using npx

npx create-react-app react-frontend

Using npm

npm init react-app react-frontend
npm init is available in npm 6+

Using Yarn

yarn create react-app react-frontend
Running any of these commands will create a directory called react-frontend inside the current folder. Inside that directory, it will generate the initial project structure and install the transitive dependencies:
my-app
├── README.md
├── node_modules
├── package.json
├── .gitignore
├── public
│   ├── favicon.ico
│   ├── index.html
│   ├── logo192.png
│   ├── logo512.png
│   ├── manifest.json
│   └── robots.txt
└── src
    ├── App.css
    ├── App.js
    ├── App.test.js
    ├── index.css
    ├── index.js
    ├── logo.svg
    └── serviceWorker.js
Let's explore important files and folders of the react project.
For the project to build, these files must exist with exact filenames:
  • public/index.html is the page template;
  • src/index.js is the JavaScript entry point. 
You can delete or rename the other files.

Let's quickly explore the project structure.

package.json - The package.json file contains all the required dependencies for our React JS project. Most importantly, you can check the current version of the React that you are using. It has all the scripts to start, build, and eject our React app.
public folder - The public folder contains index.html. As react is used to build a single page application, we have this single HTML file to render all our components. Basically, it's an HTML template. It has a div element with id as root and all our components are rendered in this div with index.html as a single page for the complete react app.
src folder- In this folder, we have all the global javascript and CSS files. All the different components that we will be building, sit here.
index.js - This is the top renderer of your react app. 
node_modules - All the packages installed by NPM or Yarn will reside inside the node_modules folder.
App.js - The App.js file contains the definition of our App component which actually gets rendered in the browser and this is the root component.

2. Adding Bootstrap in React Using NPM

Open a new terminal window, navigate to your project's folder, and run the following command:
$ npm install bootstrap --save
After installing the bootstrap package, you will need to import it in your React app entry file.
Open the src/index.js file and add the following code:
import 'bootstrap/dist/css/bootstrap.min.css';

src/index.js

Here is the complete code for index.js file:
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import 'bootstrap/dist/css/bootstrap.min.css';

ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();

3. Installing the Axios Client

Let's install the Axios library in our React project using the following command from your project's root folder:
$ npm install --save axios

4. React Service Component - REST API Call

Let's create APIService.js service implementation to make our HTTP REST call via Axios. 
Our backend USER endpoint is available at http://localhost:8080/books
import axios from 'axios';

const BOOK_API_REST_URL = "http://localhost:8080/books";

class APIService {
    
    getBooks(){
        return axios.get(BOOK_API_REST_URL);
    }

}

export default new APIService();
Make sure that you create an object of APIService class export it as:
export default new APIService();
We use the axios.get() method for sending an HTTP GET request to the /books endpoint of the REST API.

5. Develop a React Component

Let's create a BookComponent.js file and add the following code to it.
import React from 'react'
import APIService from '../service/APIService'

export default class BookComponent extends React.Component {

    constructor(props) {
        super(props)
    
        this.state = {
             books: []
        }
    }
    
    componentDidMount(){
        APIService.getBooks().then((data) => {
            this.setState({ books: data })
            console.log(this.state.data)
          })
          .catch(function (ex) {
              console.log('Response parsing failed. Error: ', ex);
          });;
    }

    render() {
        return (
            <div>
                <h2 className="text-center">Book Details</h2>
                <table className="table table-striped">
                    <thead>
                        <tr>
                            <th>Book Id</th>
                            <th>Book Name</th>
                            <th>Book Author</th>
                        </tr>
                    </thead>
                    <tbody>
                        {
                            this.state.books.map(book =>
                                    <tr key={book.id}>
                                        <td>{book.id}</td>
                                        <td>{book.bookName}</td>
                                        <td>{book.author}</td>
                                    </tr>
                            )
                        }
                    </tbody>
                </table>
            </div>
        )
    }
}
Let's understand the above code step by step.
  • constructor() - The constructor() is invoked before the component is mounted. In the constructor, we have declared our book state variable:
 constructor(props) {
        super(props)
    
        this.state = {
             books: []
        }
    }
  • componentDidMount() - The componentDidMount() is called as soon as the component is mounted and ready. This is a good place to initiate API calls if you need to load data from a remote endpoint. Note that we are calling the loadBooks() method of APIService from componentDidMount() method:
 componentDidMount(){
        APIService.getBooks().then((data) => {
            this.setState({ books: data })
            console.log(this.state.data)
          })
          .catch(function (ex) {
              console.log('Response parsing failed. Error: ', ex);
          });;
    }
  • render() - The render() method is the most used lifecycle method. You will see it in all React classes. This is because render() is the only required method within a class component in React. The render() method that actually outputs HTML to the DOM.
  • APIService - We are using APIService class to getBooks() method which interns make an API call.
We are using the map operator to loop over our book list and create the view like:
{
 this.state.books.map(book =>
   <tr key={book.id}>
    <td>{book.id}</td>
    <td>{book.bookName}</td>
                                <td>{book.author}</td>
   </tr>
 )
}

6. App.js

In the previous step, we have created BookComponent so let's go ahead add BookComponent to App component:
import React from 'react';
import logo from './logo.svg';
import './App.css';
import BookComponent from './components/BookComponent';

function App() {
  return (
    <div>
      <header className="container">
         <BookComponent />
      </header>
    </div>
  );
}

export default App;

7. Run React App

Use below command to start the project:
npm start
Use yarn to start the project:
yarn start
Runs the app in development mode. Open http://localhost:3000 to view it in the browser.

Conclusion

In this tutorial, we have developed a simple React application to consume the Spring Boot REST API using the Axios library.
Learn more about how to make GET, POST, PUT and DELETE HTTP calls using Axios library at https://www.javaguides.net/2020/07/react-js-crud-application-example.html

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