使用?? Hibernate時(shí),可以由POJO生產(chǎn)出hbm.xml映射文件和數(shù)據(jù)庫,前提是必須在POJO中使用XDoclet.的@Hibernate.Tags插件.(或JDK5的注解)
與XDoclet 1 不同,XDoclet 2在Codehaus.org上,
! XDoclet 2顯式地支持復(fù)合主鍵.
簡(jiǎn)單的使用介紹在Hibernate的文檔中可見:? http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#mapping-xdoclet
詳細(xì)的tag說明
X1:?? http://xdoclet.sourceforge.net/xdoclet/tags/hibernate-tags.html
X2:?? http://xdoclet.codehaus.org/HibernateTags
續(xù)：POJO－－XDoclet 1－－h(huán)bm.xml的過程中，如果表具有復(fù)合主鍵，標(biāo)簽要怎么寫？
環(huán)境：MyEclipse 5.0GA中包含的XDoclet插件版本仍僅支持XDoclet 1，為了不增加額外的插件，就用它了；
解決方法紀(jì)要：
我在通用報(bào)表系統(tǒng)5.0設(shè)計(jì)器的開發(fā)中使用XDoclet來生成Hibernate映射文件，遇到了復(fù)合主鍵的問題。在具有復(fù)合主鍵的情況下，我的POJO采用一個(gè)主鍵Bean的方式加一個(gè)屬性Bean的方式，（因?yàn)閄1的@hinernate.id 在每個(gè)class中最多只能有一個(gè)，多于1的會(huì)自動(dòng)忽略）也即“Components as composite identifiers” 方式。這方面的資料實(shí)在太少，東查西找，沒有解決，又連猜帶蒙，試驗(yàn)了幾十遍才搞定了，哀啊！怎么文檔這么殘呢！
關(guān)于如何在Myeclipse中使用xdoclet就不提了，把兩個(gè)POJO貼出來，一切就清楚了：
/**/
/*
*?此JavaBean由Genesis自動(dòng)生成,請(qǐng)勿隨意修改
*?生成時(shí)間:Tue?Oct?17?13:41:53?CST?2006
*/
package
?cn.tohot.grs5.po;
import
?org.apache.commons.lang.builder.EqualsBuilder;
import
?org.apache.commons.lang.builder.HashCodeBuilder;
import
?org.apache.commons.lang.builder.ToStringBuilder;
import
?org.apache.commons.lang.builder.ToStringStyle;
import
?java.math.BigDecimal;????
/**?*/
/**
?*?@hibernate.class?table="detail"
?
*/
public
?
class
?TestDetailPO?
{?
????
/**?*/
/**
?????*?復(fù)合主鍵
?????
*/
?????
private
?cn.tohot.grs5.po.TestDetailPK?pk?;
??????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.id?class="cn.tohot.grs5.po.TestDetailPK"
?????
*/
????
????
public
?cn.tohot.grs5.po.TestDetailPK?getPk?()?
{
????????
return
?pk;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setPk?(?cn.tohot.grs5.po.TestDetailPK?pk?)?
{
????????
this
.pk?
=
?pk;
????}
????
????
/**/
/*
?****?字段?****?
*/
????
private
?String?goods;
????
private
?BigDecimal?qty;
????
private
?BigDecimal?price;
????
private
?BigDecimal?amt;
????
private
?String?orderNo;
????????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="goods"?not-null="false"??
?????
*/
????
????
public
?String?getGoods?()?
{
????????
return
?goods;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setGoods?(?String?goods?)?
{
????????
this
.goods?
=
?goods;
????}
????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="qty"?not-null="false"??
?????
*/
????
????
public
?BigDecimal?getQty?()?
{
????????
return
?qty;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setQty?(?BigDecimal?qty?)?
{
????????
this
.qty?
=
?qty;
????}
????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="price"?not-null="false"??
?????
*/
????
????
public
?BigDecimal?getPrice?()?
{
????????
return
?price;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setPrice?(?BigDecimal?price?)?
{
????????
this
.price?
=
?price;
????}
????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="amt"?not-null="false"??
?????
*/
????
????
public
?BigDecimal?getAmt?()?
{
????????
return
?amt;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setAmt?(?BigDecimal?amt?)?
{
????????
this
.amt?
=
?amt;
????}
????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="orderNo"?not-null="false"??
?????
*/
????
????
public
?String?getOrderNo?()?
{
????????
return
?orderNo;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setOrderNo?(?String?orderNo?)?
{
????????
this
.orderNo?
=
?orderNo;
????}
????
????
/**?*/
/**
?Overriden?toString?method.
?????*?
@return
?string
?????
*/
????
public
?String?toString()?
{
????????
return
?ToStringBuilder.reflectionToString(
this
,
????????????????ToStringStyle.MULTI_LINE_STYLE);
????}
????
/**?*/
/**
?Overridden?equals?method.
?????*?
@param
?o?object
?????*?
@return
?true/false
?????
*/
????
public
?
boolean
?equals(Object?o)?
{
????????
return
?EqualsBuilder.reflectionEquals(
this
,?o);
????}
????
/**?*/
/**
?Creates?object?hash?code.
?????*?
@return
?int
?????
*/
????
public
?
int
?hashCode()?
{
????????
return
?HashCodeBuilder.reflectionHashCode(
this
);
????}
}
?
/**/
/*
*?此JavaBean由Genesis自動(dòng)生成,請(qǐng)勿隨意修改
*?生成時(shí)間:Tue?Oct?17?13:41:53?CST?2006
*/
package
?cn.tohot.grs5.po;
import
?org.apache.commons.lang.builder.EqualsBuilder;
import
?org.apache.commons.lang.builder.HashCodeBuilder;
import
?org.apache.commons.lang.builder.ToStringBuilder;
import
?org.apache.commons.lang.builder.ToStringStyle;
import
?java.io.Serializable;
/**?*/
/**
?*?detail?'s?composite?key
?
*/
public
?
class
?TestDetailPK?
implements
?Serializable?
{?
????
/**?*/
/**
?????*?TODO?請(qǐng)?jiān)O(shè)置此處的serialVersionUID值（建議根據(jù)提示由eclipse自動(dòng)生成）
?????
*/
????
//
private?static?final?long?serialVersionUID?;
????
????
/**/
/*
?****?主鍵字段?****?
*/
????
private
?Integer?lineNo;
????
private
?String?id;
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="lineNo"?not-null="true"?length="32"
?????
*/
????
????
public
?Integer?getLineNo?()?
{
????????
return
?lineNo;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setLineNo?(?Integer?lineNo?)?
{
????????
this
.lineNo?
=
?lineNo;
????}
????
????
/**?*/
/**
?????*?generated?by?Genesis
?????*?@hibernate.property?column="id"?not-null="false"?
?????
*/
????
????
public
?String?getId?()?
{
????????
return
?id;
????}
????
/**?*/
/**
?????*?generated?by?Genesis
?????
*/
????????
????
public
?
void
?setId?(?String?id?)?
{
????????
this
.id?
=
?id;
????}
????
????
/**?*/
/**
?Overriden?toString?method.
?????*?
@return
?string
?????
*/
????
public
?String?toString()?
{
????????
return
?ToStringBuilder.reflectionToString(
this
,
????????????????ToStringStyle.MULTI_LINE_STYLE);
????}
????
/**?*/
/**
?Overridden?equals?method.
?????*?
@param
?o?object
?????*?
@return
?true/false
?????
*/
????
public
?
boolean
?equals(Object?o)?
{
????????
return
?EqualsBuilder.reflectionEquals(
this
,?o);
????}
????
/**?*/
/**
?Creates?object?hash?code.
?????*?
@return
?int
?????
*/
????
public
?
int
?hashCode()?
{
????????
return
?HashCodeBuilder.reflectionHashCode(
this
);
????}
}
關(guān)鍵點(diǎn)：主鍵類不要有類級(jí)別的tag ( @hibernate Class Level Tags ),主鍵tag為@hibernate.property.
題外話：http://www.javaeye.com/topic/1604這篇帖子提到的一些觀點(diǎn)還是很有益的，值得看一看。
主要參考資料：
http://opensource.atlassian.com/projects/xdoclet/browse/XDT-729? bug討論
http://www.javaeye.com/t/10182.html? 該貼沒有完全解決問題，
XDoclet 1:?? http://xdoclet.sourceforge.net/xdoclet/tags/hibernate-tags.html
http://hibernate.bluemars.net/52.html?cmd=prntdoc?提到了復(fù)合主鍵將在后續(xù)版本中提供（看來就是X2了），并且 is heavily under-documented，暈，到現(xiàn)在也沒完成！
有空會(huì)研究一下X2中的composite-id怎么回事。