1.这是Spring的官方文档
https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-ann-requestmapping
2.老外写的，很有参考价值
https://springframework.guru/spring-requestmapping-annotation/
3.国内博客
https://www.cnblogs.com/baiduligang/p/4247164.html
https://www.iteye.com/news/32657/
https://www.yiibai.com/spring_mvc/
