如何使用Hibernate条件选择嵌套属性

我有三个实体，如注册、用户和国家。基本上，注册属于一个用户，用户属于一个国家。现在，我正在尝试从以下注册中选择国家名称

        Criteria criteria = getSession().createCriteria(Registration.class);
        ProjectionList projectionList = Projections.projectionList();
        criteria.createAlias("user.country", "usercountry");
        projectionList.add(Projections.property("usercountry.name"),"usercountry.name");
        criteria.setProjection(projectionList);
        criteria.list();

这失败了，请告诉我：

ERROR: org.hibernate.engine.jdbc.spi.SqlExceptionHelper - Unknown column 'usercountr1_.name' in 'field list'
org.hibernate.exception.SQLGrammarException: Unknown column 'usercountr1_.name' in 'field list'

生成的休眠查询：

Hibernate: select usercountr1_.name as y0_ from voucherList this_

我注意到sql中没有联接。这就是查询失败的原因吗？我如何解决这个问题？

试试类似的方法

Criteria criteria = getSession().createCriteria(Registration.class);
ProjectionList projectionList = Projections.projectionList();

criteria.createAlias("user", "u");  // here i changed 
criteria.createAlias("u.country", "usercountry");  //  here i have changed 

projectionList.add(Projections.property("usercountry.name"),"usercountry.name");
criteria.setProjection(projectionList);
criteria.list();

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谢谢，我刚刚发现我需要创建两个别名，而不是一个。可能是