Hibernate查询数据的几种形式以及HQL用法及参数的几种使用方法
Hibernate查询数据的几种方式以及HQL用法及参数的几种使用方法
Hibernate查询数据的几种方式
/**
* 第一种查询:利用query接口与HQL语句
* 1.如果查询所有字段,则list中的元素为POJO对象
* 2.如果查询若干字段,则list中的元素为对象数组
* 3.如果想返回若干字段的对象,则需要通过 new TUser(username,email)方式
*/
/**
* 第二种查询:利用criteria接口
*/
/**
* 第三种查询:利用SQLQuery接口,即原生SQL
* 1.如果查询所有字段,要加入标量设置query.addEntity(TUser.class);
* 2.如果查询若干字段,则集合中数据为对象数组
*/
/**
* 第四种查询:查询单个对象,注意get和load方法的区别
*/
HQL用法及参数的几种使用方法
/**
*按参数位置绑定
*/
/**
*按参数位置绑定
*/
/*
*使用setProperties方法
*/
Hibernate查询数据的几种方式
/**
* 第一种查询:利用query接口与HQL语句
* 1.如果查询所有字段,则list中的元素为POJO对象
* 2.如果查询若干字段,则list中的元素为对象数组
* 3.如果想返回若干字段的对象,则需要通过 new TUser(username,email)方式
*/
public void query(){ Session session = null; Query query = null; String hql = null; try { session = HibernateSessionFactory.getSession(); hql="From TUser user where user.suser='admin'"; query = session.createQuery(hql); List list = query.list(); for (Iterator iter = list.iterator(); iter.hasNext();) { TUser user = (TUser) iter.next(); System.out.println("----Query---"); System.out.println("-Suser-="+user.getSuser()); System.out.println("-Name--="+user.getName()); System.out.println("-Email-="+user.getEmail()); } } catch (Exception e) { e.printStackTrace(); }finally{ HibernateSessionFactory.closeSession(); } }
/**
* 第二种查询:利用criteria接口
*/
public void criteria(){ Session session = null; Criteria criteria = null; try { session = HibernateSessionFactory.getSession(); criteria = session.createCriteria(TUser.class); criteria.add(Restrictions.isNotNull("suser")); criteria.add(Restrictions.ilike("name", "%T%")); criteria.addOrder(Order.desc("nation")); List list = criteria.list(); for (Iterator iter = list.iterator(); iter.hasNext();) { TUser user = (TUser) iter.next(); System.out.println("----Criteria---"); System.out.println("-Suser-="+user.getSuser()); System.out.println("-Name--="+user.getName()); System.out.println("-Email-="+user.getEmail()); System.out.println("-Nation="+user.getNation()); } } catch (Exception e) { e.printStackTrace(); }finally{ HibernateSessionFactory.closeSession(); } }
/**
* 第三种查询:利用SQLQuery接口,即原生SQL
* 1.如果查询所有字段,要加入标量设置query.addEntity(TUser.class);
* 2.如果查询若干字段,则集合中数据为对象数组
*/
public void nativeSql() { Session session =null; Query query = null; String sql = null; try { session = HibernateSessionFactory.getSession(); sql = "select suser,name,email,nation from t_user"; query = session.createQuery(sql); List list = query.list(); for (Iterator iter = list.iterator(); iter.hasNext();) { Object[] obj = (Object[]) iter.next(); System.out.println("-Suser-="+obj[0]); System.out.println("-Name--="+obj[1]); System.out.println("-Email-="+obj[2]); System.out.println("-Nation="+obj[3]); } } catch (Exception e) { e.printStackTrace(); }finally{ HibernateSessionFactory.closeSession(); } }
/**
* 第四种查询:查询单个对象,注意get和load方法的区别
*/
public void getOrLoad(){ Session session = null; try { session = HibernateSessionFactory.getSession(); TUser user = (TUser)session.load(TUser.class, "test1"); System.out.println("-Suser-="+user.getSuser()); System.out.println("-Name--="+user.getName()); System.out.println("-Email-="+user.getEmail()); System.out.println("-Nation="+user.getNation()); } catch (Exception e) { e.printStackTrace(); }finally{ HibernateSessionFactory.closeSession(); } }
HQL用法及参数的几种使用方法
/**
*按参数位置绑定
*/
public void batchUpdate() { Session session = null; Transaction transaction = null; Query query = null; String hql ="update TUser set name='阿德' where suser=:user"; try { session = HibernateSessionFactory.getSession(); transaction =session.beginTransaction(); query = session.createQuery(hql); query.setString("user", "test9"); int i = query.executeUpdate(); transaction.commit(); System.out.println("--update--"+i); } catch (Exception e) { e.printStackTrace(); transaction.rollback(); }finally{ HibernateSessionFactory.closeSession(); } }
/**
*按参数位置绑定
*/
public void batchDelete() { Session session = null; Transaction transaction = null; Query query = null; String hql = "delete from t_user suser=:user"; try { session = HibernateSessionFactory.getSession(); transaction = session.beginTransaction(); query = session.createQuery(hql); query.setString("user", "test11"); int i = query.executeUpdate(); transaction.commit(); System.out.println("--delete--"+i); } catch (Exception e) { e.printStackTrace(); transaction.rollback(); }finally{ HibernateSessionFactory.closeSession(); } }
/*
*使用setProperties方法
*/
public void queryUsers() { Session session = null; Transaction transaction = null; Query query = null; String hql =null; try { session = HibernateSessionFactory.getSession(); hql = "from TUser where suser=:user"; transaction = session.beginTransaction(); query = session.createQuery(hql); TUser user = new TUser(); user.setSuser("test1"); query.setProperties(user); List list = query.list(); for (Iterator iter = list.iterator(); iter.hasNext();) { Object[] obj = (Object[]) iter.next(); System.out.println("-Suser-="+obj[0]); System.out.println("-Name--="+obj[1]); System.out.println("-Email-="+obj[2]); System.out.println("-Nation="+obj[3]); } } catch (Exception e) { e.printStackTrace(); transaction.rollback(); }finally{ HibernateSessionFactory.closeSession(); } }