SSH执行hql报错：Caused by: org.hibernate.hql.ast.QuerySyntaxException: user is not mapped [from user where username = ?]

报错信息：

ERROR Dispatcher:38 - Exception occurred during processing request: user is not mapped [from user where username = ?]; nested exception is org.hibernate.hql.ast.QuerySyntaxException: user is not mapped [from user where username = ?]ERROR Dispatcher:38 - Exception occurred