嘗試著繼承關系和xdoclet使用后，對數據庫面向對象的使用更近一步。
這次例子從開始到結束，都沒有接觸面向結構的數據庫設計；
并完全在代碼中以面向對象的形式來設計的。
hbn 的繼承映射關系有這幾種；
- 繼承關系類共同使用一個表；
- 每個子類一個表(mapping全)；
- 每個具體內一個表（mapping只有父類）。
先說說3把，感覺這點最好用-》》
繼承關系描述：
? Animals父類 -- Bird 、Reptiles；
? Animals.java
package?TableBean;
/** 動物父類
?*?@hibernate.class?
?*?table="animals"
?*/
public?class?Animals?{
????private?Integer?id?;
????private?Integer?size?;
????private?Integer?speed;
????/**
?????*?@hibernate.id
?????*?generator-class="increment"
?????*/
????public?Integer?getId()?{
????????return?id;
????}
????public?void?setId(Integer?id)?{
????????this.id?=?id;
????}
????/** 動物體積大小
?????*?@hibernate.property
?????*/
????public?Integer?getSize()?{
????????return?size;
????}
????public?void?setSize(Integer?size)?{
????????this.size?=?size;
????}
????/** 動物的移動速度
?????*?@hibernate.property
?????*/
????public?Integer?getSpeed()?{
????????return?speed;
????}
????public?void?setSpeed(Integer?speed)?{
????????this.speed?=?speed;
????}
????
}
Bird.java
package?TableBean;
/** 在xdoeclt中聲明繼承表關系
?*?@hibernate.joined-subclass?
?*?@hibernate.joined-subclass-key?
?*??column="id"
?*?
?*/
public?class?Bird?extends?Animals?{
????private?String?wings?;
????private?Integer?leg?;
????/** 鳥類翅膀描述
?????*?@hibernate.property?
?????*?@return
?????*/
????public?String?getWings()?{
????????return?wings;
????}
????public?void?setWings(String?wings)?{
????????this.wings?=?wings;
????}
????/**鳥腿描述
?????*?@hibernate.property?
?????*?@return
?????*/
????public?Integer?getLeg()?{
????????return?leg;
????}
????public?void?setLeg(Integer?leg)?{
????????this.leg?=?leg;
????}
????
}
?
Reptiles.java
package?TableBean;
/** 在xdoeclt中聲明繼承表關系
?*?@hibernate.joined-subclass?
?*?@hibernate.joined-subclass-key?
?*??column="id"
?*/
public?class?Reptiles?extends?Animals?{
????private?Integer?leg?;
????/** 爬行動物腿個數
?????*?@hibernate.property?
?????*?@return
?????*/
????public?Integer?getLeg()?{
????????return?leg;
????}
????public?void?setLeg(Integer?leg)?{
????????this.leg?=?leg;
????}
????
}
ant_xdoeclt.xml文件
<?xml?version="1.0"?encoding="UTF-8"?>
<!--?DO?NOT?EDIT?-->
<!--?This?file?is?automatically?regenerated?for?each?new?XDoclet?generation.?-->
<!--?Any?changes?you?make?to?this?file?will?be?overwritten.?If?you?want?-->
<!--?to?edit?this?file,?make?a?copy?and?rename?it?for?your?own?use.?-->
<project?name="Hbmzj?XDoclet?Generation"?default="_xdoclet_generation_"><property?file="xdoclet-build.properties"/>
<property?name="xdoclet.basedir"?value="/C:/Program?Files/MyEclipse/eclipse/plugins/com.genuitec.jboss.ide.eclipse.xdoclet.core_4.0.0/"/>
<path?id="xdoclet.classpath"><pathelement?location="E:/hibernate/Hbmzj/bin"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/rt.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/jsse.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/jce.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/charsets.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/ext/sunjce_provider.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/ext/sunpkcs11.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/ext/dnsns.jar"/>
<pathelement?location="C:/Program?Files/Java/jdk1.5.0_02/jre/lib/ext/localedata.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/antlr-2.7.5H3.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/asm-attrs.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/asm.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/c3p0-0.8.5.2.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/cglib-2.1.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/cleanimports.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/commons-collections-2.1.1.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/commons-logging-1.0.4.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/concurrent-1.3.2.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/connector.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/dom4j-1.6.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/ehcache-1.1.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/hibernate3.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jaas.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jacc-1_0-fr.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jaxen-1.1-beta-4.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jdbc2_0-stdext.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jgroups-2.2.7.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/jta.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/log4j-1.2.9.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/oscache-2.1.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/proxool-0.8.3.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/swarmcache-1.0rc2.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/xerces-2.6.2.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/xml-apis.jar"/>
<pathelement?location="D:/eclipse2/eclipse/plugins/org.junit_3.8.1/junit.jar"/>
<pathelement?location="E:/hibernate/Hbmzj/lib/MYSQL.JAR"/>
<fileset?dir="${xdoclet.basedir}">
<include?name="*.jar"/>
<exclude?name="*xjavadoc*.jar"/>
<include?name="jdk5/*.jar"/>
</fileset>
</path>
<target?name="_xdoclet_generation_"?depends="N65540"/>
<target?name="N65540"?description="Standard?Hibernate">
<taskdef?name="hibernatedoclet"
???????? classname="xdoclet.modules.hibernate.HibernateDocletTask"
???????? classpathref="xdoclet.classpath"/>
<hibernatedoclet?excludedTags="@version,@author,@todo,@see"?
?????????????? destDir="src"?
addedTags="@xdoclet-generated?at?${TODAY},@copyright?The?XDoclet?Team,@author?XDoclet,@version?${version}"?>
<fileset?dir="src"??includes="**/*.java"?>
</fileset>
<hibernate>
</hibernate>
</hibernatedoclet>
</target>
</project>
ant運行 后得到 Animals.hbm.xml 文件
使用 hbn工具 hbn2ddl 后
mysql>?desc??Animals;
+-------+---------+------+-----+---------+-------+
|?Field?|?Type????|?Null?|?Key?|?Default?|?Extra?|
+-------+---------+------+-----+---------+-------+
|?id????|?int(11)?|??????|?PRI?|?0???????|???????|
|?size??|?int(11)?|?YES??|?????|?NULL????|???????|
|?speed?|?int(11)?|?YES??|?????|?NULL????|???????|
+-------+---------+------+-----+---------+-------+
3?rows?in?set?(0.00?sec)
mysql>?desc?reptiles;
+-------+---------+------+-----+---------+-------+
|?Field?|?Type????|?Null?|?Key?|?Default?|?Extra?|
+-------+---------+------+-----+---------+-------+
|?id????|?int(11)?|??????|?PRI?|?0???????|???????|
|?leg???|?int(11)?|?YES??|?????|?NULL????|???????|
+-------+---------+------+-----+---------+-------+
2?rows?in?set?(0.00?sec)
mysql>?desc?bird;
+-------+--------------+------+-----+---------+-------+
|?Field?|?Type?????????|?Null?|?Key?|?Default?|?Extra?|
+-------+--------------+------+-----+---------+-------+
|?id????|?int(11)??????|??????|?PRI?|?0???????|???????|
|?wings?|?varchar(255)?|?YES??|?????|?NULL????|???????|
|?leg???|?int(11)??????|?YES??|?????|?NULL????|???????|
+-------+--------------+------+-----+---------+-------+
3?rows?in?set?(0.00?sec)
添加測試數據：
mysql>?select?*?from?bird;
+----+-------+------+
|?id?|?wings?|?leg??|
+----+-------+------+
|??1?|?2G????|????2?|
+----+-------+------+
1?row?in?set?(0.00?sec)
mysql>?select?*?from?Animals;
+----+------+-------+
|?id?|?size?|?speed?|
+----+------+-------+
|??1?|????1?|?????9?|
|??2?|????6?|?????2?|
+----+------+-------+
2?rows?in?set?(0.00?sec)
mysql>?select?*?from?Reptiles;
+----+------+
|?id?|?leg??|
+----+------+
|??2?|????4?|
+----+------+
1?row?in?set?(0.00?sec)
測試
public?class?TestJc?extends?TestCase?{
????public?void?testJC()?throws?Exception?{
????????Session?session=?HbnFactory.currentSession();
????????Transaction?tr?=?session.beginTransaction();
??????? //1
????????Animals?aa?=?(Animals)session.load(Animals.class,1);
????????System.out.println(aa);
??????? //2
????????Bird?bb?=??(Bird)?session.load(Bird.class,1);
????????System.out.println(bb);
??????? //3
????????Object?obj?=?session.createQuery("?from?Animals?").list();
????????System.out.println(obj);
????????
????????tr.commit();
????????HbnFactory.closeSession();
????}
}
結果：
//1
Hibernate:?select?animals0_.id?as?id0_,?animals0_.size?as?size0_0_,?animals0_.speed?as?speed0_0_,?animals0_1_.wings?as?wings1_0_,?animals0_1_.leg?as?leg1_0_,?animals0_2_.leg?as?leg2_0_,?case?when?animals0_1_.id?is?not?null?then?1?when?animals0_2_.id?is?not?null?then?2?when?animals0_.id?is?not?null?then?0?end?as?clazz_0_?from?animals?animals0_?left?outer?join?Bird?animals0_1_?on?animals0_.id=animals0_1_.id?left?outer?join?Reptiles?animals0_2_?on?animals0_.id=animals0_2_.id?where?animals0_.id=?
TableBean.Bird@5e176f
//2
TableBean.Bird@5e176f
//3
Hibernate:?select?animals0_.id?as?id,?animals0_.size?as?size0_,?animals0_.speed?as?speed0_,?animals0_1_.wings?as?wings1_,?animals0_1_.leg?as?leg1_,?animals0_2_.leg?as?leg2_,?case?when?animals0_1_.id?is?not?null?then?1?when?animals0_2_.id?is?not?null?then?2?when?animals0_.id?is?not?null?then?0?end?as?clazz_?from?animals?animals0_?left?outer?join?Bird?animals0_1_?on?animals0_.id=animals0_1_.id?left?outer?join?Reptiles?animals0_2_?on?animals0_.id=animals0_2_.id
[TableBean.Bird@5e176f,?TableBean.Reptiles@2c1e6b,?TableBean.Reptiles@811c88]