初学Hibernate之Query扩展

1、hql参数化查询，不明确值类型的用setParameter方法；明确查询结果为一条记录的用uniqueResult方法查询

注意，参数化查询中方法setString 或 setParameter如果使用索引方式赋值，索引值从0开始，区别JDBC

public void func1(){
    Session session=HibernateUtils.getSession();
    session.beginTransaction();
    String hql="from Customer where name=:name";
    Query query=session.createQuery(hql);
    //传参数
    //query.setString("name", "Tom");或者下面
　　query.setParameter("name", "Tom");
    //List<Customer>cusList=query.list();
   //如果明确知道查询结果就一条记录，则用下面方法
　　Customer customer=(Customer) query.uniqueResult();

    session.getTransaction().commit();
    session.close();
    //System.out.println(cusList.get(0).getName());
　　System.out.println(customer.getName());
}

2、hql分页查询

public void func2(){
    Session session=HibernateUtils.getSession();
    session.beginTransaction();
    Query query=session.createQuery("from Customer");
    //设置起始行索引
    query.setFirstResult(1);
    //设置最多返回记录数量
    query.setMaxResults(2);
    List<Customer>cusList=query.list();
    session.getTransaction().commit();
    session.close();
    System.out.println(cusList.get(0).getName()+","+cusList.get(0).getId());
    System.out.println(cusList.get(1).getName()+","+cusList.get(1).getId());
    
}

3、qbc分页查询

public void func1(){
    Session session=HibernateUtils.getSession();
    session.beginTransaction();
    
    Criteria criteria=session.createCriteria(Customer.class);
    //设置起始行索引
    criteria.setFirstResult(1);
    //设置最多返回记录数量
    criteria.setMaxResults(2);
    List<Customer>cusList=criteria.list();
    
    System.out.println(cusList.get(0).getName()+","+cusList.get(0).getId());
    System.out.println(cusList.get(1).getName()+","+cusList.get(1).getId());
    session.getTransaction().commit();
    session.close();
}

4、qbc条件查询

public void func2(){
    Session session=HibernateUtils.getSession();
    session.beginTransaction();
    Criteria criteria=session.createCriteria(Customer.class);
    //设置查询条件，name等于Tom的
    criteria.add(Restrictions.eq("name", "Tom"));
    //已明确查询结果为一条记录
    Customer customer=(Customer) criteria.uniqueResult();
    
    session.getTransaction().commit();
    session.close();
    System.out.println(customer.getName());
}

5、qbc复杂条件查询

public void func3(){
    Session session=HibernateUtils.getSession();
    session.beginTransaction();
    Criteria criteria=session.createCriteria(Customer.class);
    //设置查询条件，name等于Tom的
    criteria.add(Restrictions.eq("name", "Jack")).add(Restrictions.or(Restrictions.gt("id", 3), Restrictions.eq("city", "上海")));
    List<Customer> cusList=criteria.list();
    
    session.getTransaction().commit();
    session.close();
    for (int i = 0; i < cusList.size(); i++) {
        System.out.println(cusList.get(i).getId());
    }
}