嚴重: Servlet.service() for servlet [spring-mvc] in context with path [/learn] threw exception [Request processing failed; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'admin' for key 'UK_dgxl7aijrr4hq8314exhw407s'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
1、MySQLIntegrityConstraintViolationException是指外鍵出錯了
2、Duplicate entry 'admin'for key 'PRIMARY'是指重復了 我的用戶名設為唯一了