SpringBoot允许跨域无效原因

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;
/**

允许跨域
解决浏览器端如下报错：
<br>Access to XMLHttpRequest at 'http://localhost:8081/Ass/login'
<br>from origin 'http://localhost:8080' has been blocked by CORS policy:
<br>Response to preflight request doesn't pass access control check:
<br>No 'Access-Control-Allow-Origin' header is present on the requested resource.
<p>CORS支持跨域配置不生效且报的比上面的少了一行是因为路径错误（例如下面的少了Ass）
<br>Access to XMLHttpRequest at 'http://localhost:8081/list'
<br>from origin 'http://localhost:8080' has been blocked by CORS policy:
<br>No 'Access-Control-Allow-Origin' header is present on the requested resource.

/

@Configuration

public class CorsConfig {

@Bean

public CorsFilter corsFilter() {

final UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();

final CorsConfiguration configuration = new CorsConfiguration();

// 是否允许请求带有验证信息

configuration.setAllowCredentials(true);

// 允许访问的客户端域名

configuration.addAllowedOrigin("");

// 允许服务端访问的客户端请求头

configuration.addAllowedHeader("");

// 允许访问的方法名,GET POST等

configuration.addAllowedMethod("");

source.registerCorsConfiguration("/**", configuration);

return new CorsFilter(source);

}

}

  // 携带 cookie 以便 session 生效

axios.defaults.withCredentials=true;