Example of how to send a get and post request that works with a Spring Boot application

Message.java

package ie.gmit.sw.controllers;

/*
POJO class, just needs an empty constructor
and getters and setters.

returned as 

{
    "name": name,
    "id" : id
}

*/

public class Message {
    private String name;
    private int id;

    public Message() {

    }

    Message(String name, int id) {
        this.name = name;
        this.id = id;
    }

    public void inc() {
        id++;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getId() {
        return id;
    }

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

poll.js

// this polling function will query the server every 5
// seconds, we can use this to continually update game state.
// small test to test connectivity to spring boot server.
function poll() {
    console.log("Polling...");

    /*
    get will be used to get a new board
     */
    $.get("/test", data => {
        // data is valid JS object, not a string.
        // test data.
        console.log("From GET");
        console.log(data.name);
        console.log(data.id);
    });

    /*
    post will be used to send moves. A1 -> B3 etc.
     */
    $.ajax({
        type: "POST",
        contentType: "application/json", // this is required by spring boot. Otherwise get a 415 error.
        data: JSON.stringify({id: 10, name: "Test Post Name"}), // send object as string to server
        url: window.location + "games",
        success: e => {
            console.log(e);
        },
        error: e => {
            console.log(e);
        }
    });

    setTimeout(poll, 5000)
}
setTimeout(poll, 5000);

TestController.java

package ie.gmit.sw.controllers;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

// needs to be marked as a RestController to provide endpoints
@RestController
public class TestController {

    /* if you navigate to localhost:8080/test you get the json response
    {
        "name" : "Hello World",
        "id" : 123
    }
    */
    @RequestMapping("/test")
    public ResponseEntity<Message> test() {
        return new ResponseEntity<>(new Message("Hello World", 123), HttpStatus.OK);
    }

    /*
    a post request of an object with a name and id will be converted 
    into a Message object with those attributes.
    */
    @PostMapping(value = "/games")
    public ResponseEntity<Message> addOne(@RequestBody Message message) {
        message.inc();
        return ResponseEntity.ok(message);
    }

}