hibernate实例简析-hibernate_lazy_for_single_end

hibernate在单端关联上的lazy策略，可以取值：false/proxy/noproxy

<class>标签上的lazy不会影响到单端关联上的lazy特性
===
<hibernate-mapping>
<class name="com.bjsxt.hibernate.Group" table="t_group">
<id name="id">
<generator class="native"/>
</id>
<property name="name"/>
</class>
</hibernate-mapping>
---
<hibernate-mapping>
<class name="com.bjsxt.hibernate.User" table="t_user" lazy="false">
<id name="id">
<generator class="native"/>
</id>
<property name="name"/>
<!--
<many-to-one name="group" column="groupid" cascade="all"/>
-->
<many-to-one name="group" column="groupid"/>
</class>
</hibernate-mapping>

===
/**
* 所有lazy属性默认**/
//不会发出sql
User user = (User)session.load(User.class, 1);

//会发出sql
System.out.println("user.name=" + user.getName());

//不会发出sql
Group group = user.getGroup();

//会发出sql
System.out.println("group.name=" + group.getName());
===
/**
* 将<many-to-one>中的lazy设置为false,其它默认**/
//不会发出sql
User user = (User)session.load(User.class, 1);

//会发出sql，发出两条sql分别加载User和Group
System.out.println("user.name=" + user.getName());

//不会发出sql
Group group = user.getGroup();

//不会发出sql
System.out.println("group.name=" + group.getName());
===
/**
* <class>标签上的lazy=false,其它默认**/
//会发出sql
User user = (User)session.load(User.class, 1);

//不会发出sql
System.out.println("user.name=" + user.getName());

//不会发出sql
Group group = user.getGroup();

//会发出sql
System.out.println("group.name=" + group.getName());
===
Group group = new Group();
group.setName("尚学堂");

session.save(group);

User user1 = new User();
user1.setName("菜10");
user1.setGroup(group);

User user2 = new User();
user2.setName("容祖儿");
user2.setGroup(group);

//可以正确存储
session.save(user1);
session.save(user2);