User user = (User) session.load(
"com.jaeson.hibernatestudy.bean.User", "402881e5529691a701529691a8920000");
user.getUserId();
user.getUserName();
user.getDepartment().getDeptName();
user.getIdCard().getCardNo();
user.getRoles().toArray();
User.hbm.xml:
<many-to-one name="department" class="com.jaeson.hibernatestudy.bean.Department" fetch="select">
<column name="deptId" length="32" not-null="true" />
</many-to-one>
<one-to-one name="idCard" property-ref="user"></one-to-one>
<set name="roles" table="user_role" catalog="db4myeclipse">
<key>
<column name="userId" length="32" not-null="true" />
</key>
<many-to-many entity-name="com.jaeson.hibernatestudy.bean.Role">
<column name="roleId" not-null="true" />
</many-to-many>
</set>
默认值：
<class lazy=(true/false)> 默认为true
<component lazy=(true/false)> 默认为false
<many-to-one lazy=(proxy/no-proxy/false)> 默认为proxy
<one-to-one lazy=(proxy/no-proxy/false)> 默认为proxy
<set lazy=(true/extra/false)> 默认为true
使用默认值load时：hibernate返回的是User的代理对象，User对象的属性都没有被初始化，具体的初始化操作将有handler执行。
其中initialized是初始化标志，target则是在初始化时保存真正的User对象。
在当执行user.getUserId()时，hibernate直接返回handler属性的id值，不会进行数据库查询操作。
当执行user.getUserName()时，hibernate开始真正执行数据库查询，初始化User，此时initialized=true，target持有真正的User对象。
Hibernate: select user0_.userId as userId4_1_, user0_.deptId as deptId4_1_, user0_.userName as userName4_1_, user0_.address as address4_1_, user0_.zipCode as zipCode4_1_, user0_.phone as phone4_1_, idcard1_.id as id0_0_, idcard1_.userId as userId0_0_, idcard1_.cardNo as cardNo0_0_, idcard1_.authDate as authDate0_0_ from db4myeclipse.user user0_ left outer join db4myeclipse.idcard idcard1_ on user0_.userId=idcard1_.userId where user0_.userId=?
target持有的User对象初始化了：基本属性userName，组件属性address，one2one属性idCard；
many2one属性department则返回hibernate的代理对象。
many2many的<set>类型属性为PersistentSet，并没有加载。
当执行user.getDepartment().getDeptName()时，由department的handler进行初始化。
Hibernate: select department0_.deptId as deptId3_0_, department0_.parentId as parentId3_0_, department0_.deptName as deptName3_0_ from db4myeclipse.department department0_ where department0_.deptId=?
当执行user.getRoles().toArray()时，hibernate进行数据库操作对<set>进行初始化：
Hibernate: select roles0_.userId as userId4_1_, roles0_.roleId as roleId1_, role1_.roleId as roleId1_0_, role1_.roleName as roleName1_0_, role1_.roleDesc as roleDesc1_0_ from db4myeclipse.user_role roles0_ inner join db4myeclipse.role role1_ on roles0_.roleId=role1_.roleId where roles0_.userId=?
<class lazy="false"> class属性设为不延迟加载，其他项使用默认值时：
在执行session.load()时返回的是User对象，hibernate初始化了：基本属性userName，组件属性address，one2one属性idCard；
many2one的department返回hibernate的代理对象。
many2many的<set>类型属性为PersistentSet，并没有加载。
<class lazy="false"> class属性设为不延迟加载，many2one显式设置不延迟加载：
<many-to-one name="department" class="com.jaeson.hibernatestudy.bean.Department" lazy="false" fetch="select">
<column name="deptId" length="32" not-null="true" />
</many-to-one>
在执行session.load()时，many2one的department返回的是Department对象。