How to configure CORS in Spring Boot REST APIs?

What is CORS?

Cross-Origin Resource Sharing is a security feature that restricts web pages from making requests to a different domain than the one that served the web page.

1. Method Level:

@CrossOrigin(origins = "http://localhost:3000")
@GetMapping("/users")
public List<User> getUsers() { ... }

2. Global Configuration:

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("http://localhost:3000")
                .allowedMethods("GET", "POST", "PUT", "DELETE");
    }
}