我想在我的angular项目中使用http://5.160.2.148:8091/api/trainTicketing/city/findAll个rest for get cities
Access to XMLHttpRequest at 'http://5.160.2.148:8091/api/trainTicketing/city/findAll' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
While at work correctly when enter url in browser and postman.
为什么？