Hibernate之Query接口的uniqueResult()方法

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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();      }

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