1. Object/Relational Mapping with Hibernate
Practical ORM

2. 基础配置
Managed environment—池资源像database connections和 允许transaction,security 靠指定的声明
Non-managed environment—提供基本的并发管理通过线程池,不提供自动transaction or resource management or 安全机制. 自己管理database connections和划分transaction边界

3. 非管理环境的配置
Using a connection pool
C3P0,Apache DBCP and Proxool.

4. Using hibernate.properties for C3P0 connection pool settings
hibernate.connection.driver_class = org.postgresql.Driver
hibernate.connection.url = jdbc:postgresql://localhost/auctiondb
hibernate.connection.username = auctionuser
hibernate.connection.password = secret
hibernate.dialect = net.sf.hibernate.dialect.PostgreSQLDialect
hibernate.c3p0.min_size=5
hibernate.c3p0.max_size=20
hibernate.c3p0.timeout=300
hibernate.c3p0.max_statements=50（缓存中最大的prepared statements 数）
hibernate.c3p0.idle_test_period=3000（释放连接）

5. 管理环境的配置

6. Sample hibernate.properties for a container-provided datasource
hibernate.connection.datasource =java:/comp/env/jdbc/AuctionDB
hibernate.transaction.factory_class = \
net.sf.hibernate.transaction.JTATransactionFactory（CMT）
hibernate.transaction.manager_lookup_class = \
net.sf.hibernate.transaction.JBossTransactionManagerLookup
hibernate.dialect = net.sf.hibernate.dialect.PostgreSQLDialect

7. Using XML-based configuration
<?xml version='1.0'encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"
<hibernate-configuration>
<session-factory name="java:/hibernate/HibernateFactory">
<property name="show_sql">true</property>
<property name="connection.datasource">java:/comp/env/jdbc/AuctionDB</property>
<property name="dialect">net.sf.hibernate.dialect.PostgreSQLDialect</property>
<property name="transaction.manager_lookup_class">
net.sf.hibernate.transaction.JBossTransactionManagerLookup
</property>
<mapping resource="auction/Item.hbm.xml"/>
<mapping resource="auction/Category.hbm.xml"/>
<mapping resource="auction/Bid.hbm.xml"/>
</session-factory>
</hibernate-configuration>

8. JNDI-bound SessionFactory
hibernate.connection.datasource = java:/comp/env/jdbc/AuctionDB
hibernate.transaction.factory_class = \
net.sf.hibernate.transaction.JTATransactionFactory
hibernate.transaction.manager_lookup_class = \
net.sf.hibernate.transaction.JBossTransactionManagerLookup
hibernate.dialect = net.sf.hibernate.dialect.PostgreSQLDialect
hibernate.session_factory_name = hibernate/HibernateFactory
hibernate.jndi.class = com.sun.jndi.fscontext.RefFSContextFactory
hibernate.jndi.url = file:/auction/jndi

9. log4j.properties ### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE}
➾ %5p %c{1}:%L - %m%n
### root logger option ###
log4j.rootLogger=warn, stdout
### Hibernate logging options ###
log4j.logger.net.sf.hibernate=info
### log JDBC bind parameters ###
log4j.logger.net.sf.hibernate.type=info
### log PreparedStatement cache activity ###
log4j.logger.net.sf.hibernate.ps.PreparedStatementCache=info

10. POJO implementation of the User class
public class User implements Serializable {
private String username;
private Address address;
public User() {}
public String getUsername() {
return username;}
public void setUsername(String username) {
this.username = username;}
public Address getAddress() {
return address;}
public void setAddress(Address address) {
this.address = address;}
public MonetaryAmount calcShippingCosts(Address fromLocation) { }

11. Implementing POJO associations
Category aParent = new Category();
Category aChild = new Category();
aChild.setParentCategory(aParent);
aParent.getChildCategories().add(aChild);

12. many-to-many association

13. Hibernate XML mapping of the Category class

14. Basic property and class mappings
<property name="description" column="DESCRIPTION" type="string"/>
<property name="description" column="DESCRIPTION"/>
以上配置是等同的，以下配置是等同的
<property name="description" type="string">
<column name="DESCRIPTION"/>
</property>
<property name="initialPrice" column="INITIAL_PRICE" not-null="true"/>

15. 使用合成属性 <property name="totalIncludingTax"
formula="TOTAL + TAX_RATE * TOTAL"
type="big_decimal"/>
<property
name="averageBidAmount"
formula="( select AVG(b.AMOUNT) from BID b
➾where b.ITEM_ID = ITEM_ID )"

16. Property access strategies
<property name="name"
column="NAME"
type="string"
access=“field”/>(这种配置不需要get()/set())
Default uses the property accessors(get/set method pair)
The field strategy uses reflection to access the instance variable directly

17. 控制插入和更新 immutable=“false”设置改属性为只读 只插入\更新需要的属性 <property name="name"
column="NAME"
type="string"
insert="false"
update="false"/>
immutable=“false”设置改属性为只读
<class name="org.hibernate.auction.model.User"
dynamic-insert="true"
dynamic-update="true">
...
</class>
只插入\更新需要的属性

18. Using quoted SQL identifiers
<property name="description"
column="`Item Description`"/>

19. SQL schemas <hibernate-mapping> <class
name="org.hibernate.auction.model.Category"
table="CATEGORY"
schema="AUCTION">
...
</class>
</hibernate-mapping>
在整个文档中声明:
<hibernate-mapping
default-schema="AUCTION"> ..

20. Declaring class names <?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"
<hibernate-mapping>
<class
name="org.hibernate.auction.model.Category"
table="CATEGORY">
...
</class>
</hibernate-mapping>
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"
<hibernate-mapping
package="org.hibernate.auction.model">
<class
name="Category"
table="CATEGORY">
...
</class>
</hibernate-mapping>

21. Manipulating metadata at runtime
// Get the existing mapping for User from Configuration
PersistentClass userMapping = cfg.getClassMapping(User.class);
// Define a new column for the USER table
Column column = new Column();
column.setType(Hibernate.STRING);
column.setName("MOTTO");
column.setNullable(false);
column.setUnique(true);
userMapping.getTable().addColumn(column);
// Wrap the column in a Value
SimpleValue value = new SimpleValue();
value.setTable( userMapping.getTable() );
value.addColumn(column);
value.setType(Hibernate.STRING);
// Define a new property of the User class
Property prop = new Property();
prop.setValue(value);
prop.setName("motto");
userMapping.addProperty(prop);
// Build a new session factory, using the new mapping
SessionFactory sf = cfg.buildSessionFactory();

22. Database identity with Hibernate
持久化实例的identifier property的值
这个值通过调用Session.getIdentifier(Object o)返回
public class Category {
private Long id;
...
public Long getId() {
return this.id; }
private void setId(Long id) {
this.id = id;
<class name="Category" table="CATEGORY">
<id name="id" column="CATEGORY_ID" type="long">
<generator class="native"/>
</id>
...
</class>
<id column="CATEGORY_ID">
<generator class="native"/>
</id>
Long catId = (Long) session.getIdentifier(category);
category.getId()；

23. 使用components

24. 使用components-2 <component name="homeAddress" class="Address">
<parent name="user"/>
<property name="street" type="string" column="HOME_STREET"/>
<property name="city" type="string" column="HOME_CITY"/>
<property name="zipcode" type="short" column="HOME_ZIPCODE"/>
</component>

25. 映射类的继承 表对应具体的类—在关系模型中放弃多态和继承（<class>）
表对应类的继承关系—能在关系模型中使用多态,使用一个类型描述的列保持数据类型信息（<subclass>）
表对应子类—把 “is a” (inheritance) 关系作为 “has a”(foreign key) 关系（<joined-subclass>）

26. 表对应具体的类

27. SQL SELECTs select CREDIT_CARD_ID, OWNER, NUMBER, CREATED, TYPE, ...
from CREDIT_CARD
where CREATED = ?
select BANK_ACCOUNT_ID, OWNER, NUMBER, CREATED, BANK_NAME, ...
from BANK_ACCOUNT
select CREDIT_CARD_ID, TYPE, EXP_MONTH, EXP_YEAR from CREDIT_CARD

28. 表对应类的继承关系

29. XML Mapping

30. SQL SELECTs 1.querying the BillingDetails class
select BILLING_DETAILS_ID, BILLING_DETAILS_TYPE,
OWNER, ..., CREDIT_CARD_TYPE,
from BILLING_DETAILS
where CREATED = ?
2. query the CreditCard subclass
select BILLING_DETAILS_ID,
CREDIT_CARD_TYPE, CREDIT_CARD_EXP_MONTH, ...
where BILLING_DETAILS_TYPE='CC' and CREATED = ?

31. 表对应子类

32. XML Mapping

33. SQL SELECTs(outer join)
1.querying the BillingDetails class
select BD.BILLING_DETAILS_ID, BD.OWNER, BD.NUMER, BD.CREATED,
CC.TYPE, ..., BA.BANK_SWIFT, ...
case
when CC.CREDIT_CARD_ID is not null then 1
when BA.BANK_ACCOUNT_ID is not null then 2
when BD.BILLING_DETAILS_ID is not null then 0
end as TYPE
from BILLING_DETAILS BD
left join CREDIT_CARD CC on
BD.BILLING_DETAILS_ID = CC.CREDIT_CARD_ID
left join BANK_ACCOUNT BA on
BD.BILLING_DETAILS_ID = BA.BANK_ACCOUNT_ID
where BD.CREATED = ?

34. SQL SELECTs(inner join)
select BD.BILLING_DETAILS_ID, BD.OWNER, BD.CREATED, CC.TYPE, ...
from CREDIT_CARD CC
inner join BILLING_DETAILS BD on
BD.BILLING_DETAILS_ID = CC.CREDIT_CARD_ID
where CC.CREATED = ?

35. Managed associations(CMP->CMR)
bid.setItem(item)->item.getBids().add(item)双向
public class Bid {
...
private Item item;
public void setItem(Item item) {
this.item = item; }
public Item getItem() {
return item;
<class
name="Bid"
table="BID">
...
<many-to-one
name="item"
column="ITEM_ID"
class="Item"
not-null="true"/>
</class> 单向

36. 双向关联关系 <class name="Item" table="ITEM"> ...
public class Item {
...
private Set bids = new HashSet();
public void setBids(Set bids) {
this.bids = bids; }
public Set getBids() {
return bids;
public void addBid(Bid bid) {
bid.setItem(this);
bids.add(bid);
<class
name="Item"
table="ITEM">
...
<set name="bids">
<key column="ITEM_ID"/>
<one-to-many class="Bid"/>
</set>
</class>
Not at all verbose!

37. 表关联(one-many)
Not at all verbose

38. One-to-one associations
<class name="Address" table="ADDRESS">
<id name="id" column="ADDRESS_ID">
<generator class="native"/>
</id>
<property name="street"/>
<property name="city"/>
<property name="zipcode"/>
</class>
<one-to-one name="user"
class="User"
property-ref="billingAddress"/>
Not at all verbose

39. 表关联（one-one） Address address = new Address();
address.setStreet("646 Toorak Rd");
address.setCity("Toorak");
address.setZipcode("3000");
Transaction tx = session.beginTransaction();
User user = (User) session.get(User.class, userId);
address.setUser(user);
user.setBillingAddress(address);
tx.commit();
Not at all verbose

40. Using a primary key association
1.single address property address and map it with the User
<one-to-one name="address"
class="Address"
cascade="save-update"/>
2.here’s the user of Address
<one-to-one name="user"
class="User"
constrained="true"/>

41. XML Mapping <class name="Address" table="ADDRESS">
<id name="id" column="ADDRESS_ID">
<generator class="foreign">
<param name="property">user</param>
</generator>
</id>
...
<one-to-one name="user"
class="User"
constrained="true"/>
</class>

42. Many-to-many associations
A unidirectional many-to-many association
<set name="items"
table="CATEGORY_ITEM"
lazy="true"
cascade="save-update">
<key column="CATEGORY_ID"/>
<many-to-many class="Item" column="ITEM_ID"/>
</set>

43. Many-to-many associations
We can also use a bag with a separate primary key column:
<idbag name="items"
table="CATEGORY_ITEM”
lazy="true"
cascade="save-update">
<collection-id type="long" column="CATEGORY_ITEM_ID">
<generator class="sequence"/>
</collection-id>
<key column="CATEGORY_ID"/>
<many-to-many class="Item" column="ITEM_ID"/>
</idbag>

44. Many-to-many associations
<list name="items"
table="CATEGORY_ITEM”
lazy="true"
cascade="save-update">
<key column="CATEGORY_ID"/>
<index column="DISPLAY_POSITION"/>
<many-to-many class="Item" column="ITEM_ID"/>
</list>

45. Many-to-many associations
Transaction tx = session.beginTransaction();
Category cat = (Category) session.get(Category.class, categoryId);
Item item = (Item) session.get(Item.class, itemId);
cat.getItems().add(item);
tx.commit();

46. Many-to-many associations
A bidirectional many-to-many association
<class name="Category" table="CATEGORY">
... <
set name="items"
table="CATEGORY_ITEM"
lazy="true"
cascade="save-update">
<key column="CATEGORY_ID"/>
<many-to-many class="Item" column="ITEM_ID"/>
</set>
</class>
A bidirectional many-to-many association
<class name="Item" table="ITEM">
...
<set name="categories"
table="CATEGORY_ITEM"
lazy="true"
inverse="true"
cascade="save-update">
<key column="ITEM_ID"/>
<many-to-many class="Item" column="CATEGORY_ID"/>
</set>
</class>

47. Understanding the Hibernate type system
Built-in mapping types
Java primitive mapping types
Using mapping types
Creating custom mapping types
Not at all verbose