MainController.java

package com.example.accessingdatamysql;


import org.apache.coyote.Response;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Map;
import java.util.HashMap;
import io.jsonwebtoken.Claims;
import com.example.accessingdatamysql.auth.AuthController;
import java.util.Optional;

@CrossOrigin
@RestController // This means that this class is a Controller
@RequestMapping(path="/user") // This means URL's start with /user (after Application path)
public class MainController {
    @Autowired // This means to get the bean called userRepository
    // Which is auto-generated by Spring, we will use it to handle the data
    private UserRepository userRepository;


    @PostMapping(path = "/add") // Map ONLY POST Requests
    @ResponseBody
    public User addJsonUser(@RequestBody User usr) {
        // @ResponseBody means the returned String is the response, not a view name
        // @RequestParam means it is a parameter from the GET or POST request
        userRepository.save(usr);
        return usr;
    }

    @PutMapping(path = "/update")
    @ResponseBody
    public User updateUser(@RequestBody User usr)
    {
        userRepository.save(usr);
        return usr;
    }

    @PutMapping(path = "/changepass")
    @ResponseBody
    public User updateUser(@RequestBody Map<String, String> json)
    {
        if (json.get("email") != null)
        {
            Optional<User> user = userRepository.findById(json.get("email"));
            if (user.isPresent())
            {
                User usr = user.get();
                usr.setPassword(json.get("password"));
                userRepository.save(usr);
                return usr;
            }
            return null;
        }
        return null;
    }

    @GetMapping(path="/all")
    public @ResponseBody Iterable<User> getAllUsers() {
        // This returns a JSON or XML with the users
        return userRepository.findAll();
    }

    @PostMapping(path = "/user")
    public @ResponseBody User getUser(@RequestBody Map<String, String> json)
    {
        User found = new User();
        AuthController au = new AuthController();
        Map<String, String> res =  au.verify(json); // if the jwt token could not be verified
        if (res.containsKey("login") && res.get("login").equals("failed"))
        {
            found.setEmail("failed");
            return found;
        }
        Optional<User> usr = userRepository.findById(res.get("user"));
        if (!usr.isPresent())
        {
            found.setEmail("not found");
            return found;
        }
        return usr.get();
    }

    @PostMapping(path = "/delete")
    @ResponseBody 
    public User deleteUser(@RequestBody Map<String, String> json)
    {
        User found = new User();
        AuthController au = new AuthController();
        Map<String, String> res =  au.verify(json); // if the jwt token could not be verified
        if (res.containsKey("login") && res.get("login").equals("failed"))
        {
            found.setEmail("failed");
            return found;
        }
        String email = res.get("user");
        Optional<User> optionalUser = userRepository.findById(email);
        if (optionalUser.isPresent())
        {
            found = optionalUser.get();
            userRepository.deleteById(email);
            return found;
        }
        found.setEmail("not found");
        return found;
    }
}