springboot版本从2.3.3.RELEASE升级到2.5.14后，前端访问后台接口提示跨域问题。

将原来的跨域配置，如下：

@Configuration
public class CorsConfig{
    @Bean
    public CorsFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedOrigin("*");
        config.setAllowCredentials(true);
        config.addAllowedMethod("*");
        config.addAllowedHeader("*");
        config.addExposedHeader("token");
        UrlBasedCorsConfigurationSource configSource = new UrlBasedCorsConfigurationSource();
        configSource.registerCorsConfiguration("/**", config);
        return new CorsFilter(configSource);
    }
}

修改为如下：

@Configuration
public class CorsConfig{
    @Bean
    public CorsFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedOriginPattern("*");
        config.addAllowedHeader("*");
        config.addAllowedMethod("*");
        config.setAllowCredentials(true);
        config.setMaxAge(3600L);
        UrlBasedCorsConfigurationSource configSource = new UrlBasedCorsConfigurationSource();
        configSource.registerCorsConfiguration("/**", config);
        return new CorsFilter(configSource);
    }
}

参考链接：
https://blog.csdn.net/xiaolegeaizy/article/details/114312969?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-1-114312969-blog-117674543.pc_relevant_downloadblacklistv1&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-1-114312969-blog-117674543.pc_relevant_downloadblacklistv1&utm_relevant_index=1