A different object with the same identifier value was already associated with the session

org.springframework.dao.DuplicateKeyException: A different object with the same identifier value was already associated with the session : [com.chuai.pojo.User#4]; nested exception is org.hibernate.NonUniqueObjectException: A different object with the same identifier value was already associated with the session : [com.chuai.pojo.User#4]


原因：
不同的对象具有同一个session，在dao层操作之前清空session即可。