Hibernate之Query接口的uniqueResult()方法

如果查询返回多个值用list()方法

public void testQuery(){ Configuration config = new Configuration().configure(); SessionFactory factory = config.buildSessionFactory(); //创建SessionFactory Session session = factory.openSession(); //创建Session session.beginTransaction(); //开始事务 Query query = session.createQuery("from Student"); List list = query.list(); // 用list方法返回多个值 //List list = session.createQuery("from Student").list(); for(int i=0;i<list.size();i++){ Student student = (Student)list.get(i); System.out.print(student.getId()+" "); System.out.print(student.getName()+" "); System.out.print(student.getSex()+" "); System.out.print(student.getBirthday()); System.out.println(); } session.getTransaction().commit(); //提交事务 session.close(); //关闭Session } 当确定返回的实例只有一个或者null时 用uniqueResult()方法

public void testGet(){ Configuration config = new Configuration().configure(); SessionFactory factory = config.buildSessionFactory(); Session session = factory.openSession(); session.beginTransaction(); Query query = session.createQuery("from Student s where s.id=?"); query.setString(0, "2"); Student student = (Student)query.uniqueResult(); //当确定返回的实例只有一个或者null时 用uniqueResult()方法 //Student student = (Student)session.createQuery("from Student s where s.id=?").setString(0,"5").uniqueResult(); System.out.println(student.getName()); System.out.println(student.getBirthday()); session.getTransaction().commit(); session.close(); }