mvc开源项目参考 https://gitee.com/YHC/book-JavaEE-SSM
spring petclinic https://gitee.com/phxism/spring-framework-petclinic
https://gitee.com/univerciti/java-ee-spring-pet-clinic
https://github.com/FlaviodosSantos/TutorialSpringMVC
https://github.com/spring-petclinic/spring-framework-petclinic
