如图：

1.在config配置包中创建一个CorsConfig配置类

2.将下面代码复制到这个类中即可

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

@Configuration
public class CorsConfig {
    @Bean
    public CorsFilter corsFilter(){
        CorsConfiguration corsConfiguration=new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*");
        corsConfiguration.addAllowedHeader("*");
        corsConfiguration.addAllowedMethod("*");
        UrlBasedCorsConfigurationSource source=new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**",corsConfiguration);
        return new CorsFilter(source);
    }
}