SpringBoot 中通过 CORS 解决跨域问题

No ‘Access-Control-Allow-Origin‘ header is present on the requested resource.

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")  //允许跨域的路径
        .allowedOrigins("*")  //允许的所有域名
        //.allowedOrigins("http://localhost:8081")  //允许的指定域名
        .allowedMethods("*")   //允许的方法
        .allowedHeaders("*");  //允许的请求头
    }
}

@RestController
public class HelloController {
    @CrossOrigin(value = "http://localhost:8081")
    @GetMapping("/hello")
    public String hello() {
        return "hello";
    }

    @CrossOrigin(value = "http://localhost:8081")
    @PostMapping("/hello")
    public String hello2() {
        return "post hello";
    }
}

@RestController
@CrossOrigin(value = "http://localhost:8081")
public class HelloController {
    @GetMapping("/hello")
    public String hello() {
        return "hello";
    }

    @PostMapping("/hello")
    public String hello2() {
        return "post hello";
    }
}