在使用map集合配置實體類型時候，其key為某一個字段，而value是這一個實體的實例
比如Team和Student一對多的關(guān)系，Team中有一個ma存放student,這個map的key為student中的cardid,而value是具體的一個student實例
需要注意的是，這樣使用時候，team端需要維護(hù)cardid,所以，不能再像set那樣可以在1端設(shè)置inverse="true"來提高性能
數(shù)據(jù)庫結(jié)構(gòu)：
?
create
?
table
?teamMapC?(id?
varchar
(
32
),teamname?
varchar
(
32
));
create
?
table
?studentMapC?(id?
varchar
(
32
),cardid?
varchar
(
32
),name?
varchar
(
32
),age?
int
,description?
varchar
(
32
),?team_id?
varchar
(
32
));
?
實體類：
?
package
?Collection.Map.Complex;
public
?
class
?Student?
{
??
private
?String?id;
??
private
?String?name;
??
private
?String?description;
??
private
?
int
?age;
??
private
?String?cardid;
??
private
?Team?team;
public
?String?getId()?
{
????
return
?id;
}
public
?
void
?setId(String?id)?
{
????
this
.id?
=
?id;
}
public
?String?getName()?
{
????
return
?name;
}
public
?
void
?setName(String?name)?
{
????
this
.name?
=
?name;
}
public
?String?getDescription()?
{
????
return
?description;
}
public
?
void
?setDescription(String?description)?
{
????
this
.description?
=
?description;
}
public
?
int
?getAge()?
{
????
return
?age;
}
public
?
void
?setAge(
int
?age)?
{
????
this
.age?
=
?age;
}
public
?String?getCardid()?
{
????
return
?cardid;
}
public
?
void
?setCardid(String?cardid)?
{
????
this
.cardid?
=
?cardid;
}
public
?Team?getTeam()?
{
????
return
?team;
}
public
?
void
?setTeam(Team?team)?
{
????
this
.team?
=
?team;
}
}
package
?Collection.Map.Complex;
import
?java.util.HashMap;
import
?java.util.Map;
public
?
class
?Team?
{
???
private
?String?id;
???
private
?String?teamname;
???
private
?Map?students
=
new
?HashMap();
public
?String?getId()?
{
????
return
?id;
}
public
?
void
?setId(String?id)?
{
????
this
.id?
=
?id;
}
public
?String?getTeamname()?
{
????
return
?teamname;
}
public
?
void
?setTeamname(String?teamname)?
{
????
this
.teamname?
=
?teamname;
}
public
?Map?getStudents()?
{
????
return
?students;
}
public
?
void
?setStudents(Map?students)?
{
????
this
.students?
=
?students;
}
}
?
Hibernate.cfg.xml
?
<?
xml?version='1.0'?encoding='UTF-8'
?>
<!
DOCTYPE?hibernate-configuration?PUBLIC
??????????"-//Hibernate/Hibernate?Configuration?DTD?3.0//EN"
??????????"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"
>
<!--
?Generated?by?MyEclipse?Hibernate?Tools.???????????????????
-->
<
hibernate-configuration
>
<
session-factory
>
????
<
property?
name
="connection.username"
>
root
</
property
>
????
<
property?
name
="connection.url"
>
????????jdbc:mysql://localhost:3306/schoolproject?characterEncoding=gb2312
&
useUnicode=true
????
</
property
>
????
<
property?
name
="dialect"
>
????????org.hibernate.dialect.MySQLDialect
????
</
property
>
????
<
property?
name
="myeclipse.connection.profile"
>
mysql
</
property
>
????
<
property?
name
="connection.password"
>
1234
</
property
>
????
<
property?
name
="connection.driver_class"
>
????????com.mysql.jdbc.Driver
????
</
property
>
????
<
property?
name
="hibernate.dialect"
>
????????org.hibernate.dialect.MySQLDialect
????
</
property
>
????
<
property?
name
="hibernate.show_sql"
>
true
</
property
>
????
<
property?
name
="current_session_context_class"
>
thread
</
property
>
????
<
property?
name
="jdbc.batch_size"
>
15
</
property
>
????
<
mapping?
resource
="Collection/Map/Complex/Student.hbm.xml"
?
/>
????
<
mapping?
resource
="Collection/Map/Complex/Team.hbm.xml"
?
/>
</
session-factory
>
</
hibernate-configuration
>
Team.hbm.xml
?
<?
xml?version="1.0"?encoding="utf-8"
?>
<!
DOCTYPE?hibernate-mapping?PUBLIC?"-//Hibernate/Hibernate?Mapping?DTD?3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"
>
<!--
?
????Mapping?file?autogenerated?by?MyEclipse?-?Hibernate?Tools
-->
<
hibernate-mapping
>
<
class?
name
="Collection.Map.Complex.Team"
?table
="teamMapC"
?
>
????
<
id?
name
="id"
?unsaved-value
="null"
>
??????
<
generator?
class
="uuid.hex"
></
generator
>
????
</
id
>
????
<
property?
name
="teamname"
?type
="string"
?column
="teamname"
></
property
>
????
<!--
由于cardid需要team來維護(hù)，所以，使用map表示1對多時候，不能再1方設(shè)置inverse="true"
-->
????
<
map?
name
="students"
?table
="studentMap"
?cascade
="all"
?
>
??????
<
key?
column
="team_id"
></
key
>
??????
<!--
?index代表key,element(或one-to-many)代表value
-->
??????
<!--
?這里用cardid作為key,具體的student實例作為value?
-->
??????
<
index?
column
="cardid"
?type
="string"
></
index
>
??????
<
one-to-many?
class
="Collection.Map.Complex.Student"
/>
????
</
map
>
</
class
>
</
hibernate-mapping
>
?
Student.hbm.xml
?
<?
xml?version="1.0"?encoding="utf-8"
?>
<!
DOCTYPE?hibernate-mapping?PUBLIC?"-//Hibernate/Hibernate?Mapping?DTD?3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"
>
<!--
?
????Mapping?file?autogenerated?by?MyEclipse?-?Hibernate?Tools
-->
<
hibernate-mapping
>
<
class?
name
="Collection.Map.Complex.Student"
?table
="studentMapC"
?
>
????
<
id?
name
="id"
?unsaved-value
="null"
>
??????
<
generator?
class
="uuid.hex"
></
generator
>
????
</
id
>
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