代码地址
https://gitee.com/zjj19941/ZJJ_Neaten5.10/tree/master/ZJJ_Gateway/demo09 
后端代码配置
通过yml配置的方式
https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#cors-configuration 
spring
  cloud
    gateway
        globalcors
          cors-configurations
            '[/**]'
              allowedOrigins"*"
              allowedMethods
GET
POST
DELETE
PUT
OPTION通过java配置的方式
public class CorsConfig {
    
    public CorsWebFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedMethod("*");
        config.addAllowedOrigin("*");
        config.addAllowedHeader("*");
 
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(new PathPatternParser());
        source.registerCorsConfiguration("/**", config);
 
        return new CorsWebFilter(source);
    }
}前端页面代码
user.html:
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="http://apps.bdimg.com/libs/jquery/1.9.1/jquery.min.js"></script>
</head>
<body>
    <div >
        <table border="1">
        <thead>
 
        </thead>
        <tbody id="userlist">
        </tbody>
    </table>
    </div>
    <input type="button" value="触发按钮" onclick="getData()">
    <script>
        function getData() {
            $.get('http://localhost:8888/order/demo01',function(data){
                alert(data);
            });
        }
    </script>
</body>
</html>直接双击浏览器打开
测试
配置跨域之前:
点击 触发按钮 报跨域错误
 

配置跨域之后:
点击 触发按钮
 
console没有报错,并且弹出来东西了
                
                










