1. What is spanning?
A webpage requests resources from another webpage with a different domain name/different protocol/different port, which is cross-domain.
2. What is the reason for cross-domain?
In the current domain name request website, sending other domain names through ajax request is not allowed by default.
3. Why is there a cross-domain request?
Because the browser uses the same-origin policy
4. What is the same-origin policy?
The protocol, domain name, and port number must be exactly the same. Violation of the same-origin policy is cross-domain.
5. Why do browsers use the same-origin policy?
It is to ensure the user's information security and prevent malicious websites from stealing data
6. Five cross-domain solutions
- Frontend uses jsonp (deprecated)
- Background Http request forwarding
- Configure same-origin Cors in the background (recommended)
- Use Spring Cloud Gateway
- Use nginx for forwarding (recommended)