React - Ajax GET request

In this article, we would like to show you how to make a simple AJAX request in React.

We use React.useState hook to store the response from the server. fetch method takes path to the resource we want to fetch, then .text() method converts data received from the server to the text and with setResponse sets the state response value.

Runnable example:

// ONLINE-RUNNER:browser;

// Note: Uncomment import lines during working with JSX Compiler.
// import React from 'react';
// import ReactDOM from 'react-dom';

const App = () => {
    const [response, setResponse] = React.useState();
    React.useEffect(() => {
        let componentRemoved = false;
        const requestText = 'hello';
        fetch(`/examples/echo?text=${encodeURIComponent(requestText)}`)
            .then(response => response.text())
            .then(responseText => {
          		if (componentRemoved) {
                	return;
                }
          		setResponse(`Response: ${responseText}`);
            })
            .catch(error => {
          		if (componentRemoved) {
                	return;
                }
            	setResponse('Request error!');
        	});
        return () => {
          	componentRemoved = true;
        };
    }, []);
    return (
      <div>{response}</div>
    );
};

const root = document.querySelector('#root');
ReactDOM.render(<App/>, root );

Spring MVC server site GET methods example

Server side logic that may handle requests for the above example can be written with Spring Framework.

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

@Controller
public class EchoGetController {

    @RequestMapping(value = "/examples/echo", method = RequestMethod.GET)
    @ResponseBody
    public String makeGetEcho(@RequestParam("text") String text) {
        return text;
    }
}

See also

1. JavaScript Ajax GET request with Java Spring MVC controller