hibernate_CURD操作

1. 保存记录
 其中，customer是一个实例类对象。
session.save(customer);

2. 根据主键进行查询
* Customer customer = (Customer)session.get(Customer.class ,1);
* Customer customer = (Customer)session.load(Customer.class,1);

3. 修改记录
 session.update(customer);
修改有两种方式：

//第一种:手动创建对象的方式
Customer customer = new Customer();
customer.setId(2);
customer.setName("苍老师");        
session.update(customer);
***** 这种方式如果没有设置的属性,将这个属性的默认值存入了.(不好.)

//第二种:先查询在修改的方式(推荐方式)
Customer customer = (Customer) session.get(Customer.class, 1);
customer.setName("凤姐");
session.update(customer);

4. 删除记录
 session.delete(customer);
删除有两种方式:

//第一种:手动创建对象的方式
Customer customer = new Customer();
customer.setId(2);
session.delete(customer);

//第二种:先查询在删除的方式
Customer customer = (Customer)session.get(Customer.class, 1);
session.delete(customer);

5. 查询所有
<1>HQL:Hibernate Query Language.
面向对象的写法:

Query query = session.createQuery("from Customer where name = ?");
query.setParameter(0, "苍老师");
Query.list();

<2>QBC:Query By Criteria.(条件查询)

Criteria criteria = session.createCriteria(Customer.class);
criteria.add(Restrictions.eq("name", "凤姐"));
List<Customer> list = criteria.list();

<3>SQL

SQLQuery query = session.createSQLQuery("select * from customer");
List<Object[]> list = query.list();

SQLQuery query = session.createSQLQuery("select * from customer");
query.addEntity(Customer.class);
List<Customer> list = query.list();