Spring Boot : Enable CORS

If you have client app running on http://localhost:4200 and it make a request to API written in Spring Boot that is running on http://localhost:8080, You should get the below error because client app and API has a different origin (domain, protocol or port).

Access to XMLHttpRequest at 'http://localhost:8080/hello' from origin 'http://localhost:4200' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

You can resolve this problem by enable CORS in Spring Boot.

• At Class or Method level

@RestController
public class MainController {

    @CrossOrigin(origins = "http://localhost:4200")
    @GetMapping("/hello")
    public User hello() throws Exception {
        return User.builder().name("Mac").build();
    }
}

• Global ```java

@Configuration
public class WebConfig {

@Bean
public WebMvcConfigurer corsConfigurer() {
    return new WebMvcConfigurer() {
        @Override
        public void addCorsMappings(CorsRegistry registry) {
            registry.addMapping("/**").allowedOrigins("http://localhost:4200");
        }
    };
}

}