例如代码
User user = new User(); user.setQq(323222); user.setName("abolo"); Grade g = new Grade(); Grade grade = new Grade(); grade.setName("ww"); grade.setClassNum(44); user.setGrade(grade); session.save(user); // session.save(grade);
虽然没保存grade,但是保存了user,user关联了grade,所以grade也保存了。配置中并没设置,这都是hibernate默认的