【Hibernate】session.createQuery的参

参数绑定: 都支持位置绑定和命名绑定
如: Java代码

session.createQuery("from Person where id=:id").setInteger("id",1);   
session.createQuery("from Person where id=?").setInteger(0,1);  

**基本的参数绑定: **
setString();
setInteger();
等...
**特殊的参数绑定 **

1. setEntity()

Customer customer = new Customer();   
customer.setId(1);   
session.createQuery("from Order o where o.customer =:customer ").setEntity("customer", customer);  

等价于

session.createQuery("from Order o where o.customer.id =:customerid ").setInteger("customerid", 1);  

2. setParameter()

Query query = session.createQuery("from Order o where o.customer=:customer and o.orderNumber like :orderNumber");
query.setParameter("customer", customer, Hibernate.entity(Customer.class)); 

对于某些参数,Hibernate能跟根据参数值的Java类型推断出对应的映射类型,此时不需要在setParameter()方法中显式指定映射类型,如:

Query query = session.createQuery("from Order o where o.customer=:customer and o.orderNumber like :orderNumber");   
query.setParameter("customer", customer);   
query.setParameter("orderNumber", orderNumber);  

对于日期类型,如java.util.Date类型,会对应多种Hibernate映射类型,如Hibernate.DATE或Hibernate.TIMESTAMP,因此必须在setParameter()方法中显式指定到底对应哪种Hibernate映射类型,如:

Query query = session.createQuery("from Customer c where c.birthday=:birthday");   
query.setParameter("birthday",birthday,Hibernate.DATE);  

3. setProperties()方法:用于把命名参数与一个对象的属性值绑定,如:

Customer customer = new Customer();   
customer.setName("Tom");   
customer.setAge(21);   
Query query = session.createQuery("from Customer as c where c.name=:name and c.age="age");   
query.setProperties(customer);  

setProperties()调用setParameter()方法,setParameter()方法再根据Customer对象的属性的Java类型来推断Hibernate映射类型.如果命名参数为日期类型,不能通过setProperties()方法来绑定.
参数绑定对null是安全的.