利用Hibernate Synchronizer插入oralce.CLOB字段
2024-07-21 02:40:10
供稿：网友
表info的映射文件info.xml为：<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" ><hibernate-mapping>
<class name="src.Info" table="INFO">
<id
column="INFO_ID"
name="Id"
type="integer"
>
<generator class="vm">
<!--param name="INFO">info_id</param-->
<!--param name="INFO_ID">next_hi_value_column</param-->
</generator> </id>
<PRoperty
column="INFO_CONT"
name="InfoCont"
not-null="false"
type="java.sql.Clob"
/>
<property
column="INFO_AREA"
length="100"
name="InfoArea"
not-null="false"
type="string"
/>
<property
column="INFO_DATE"
length="7"
name="InfoDate"
not-null="false"
type="date"
/>
</class>
</hibernate-mapping>
其中红色字体为要映射的Oracle.CLOB类型。（在这里将其类型定义为java.sql.Clob类型，假如定义为oracle.CLOB，在运行时，会抛出异常net.sf.hibernate.MappingException: Error reading resource: Info.hbmnet.sf.hibernate.MappingException: Error reading resource: Info.hbm。我也不明白为什么，估计是找不到包，假如那位知道，请告诉我！）下面是相应的代码片断： // Load the configuration file
_RootDAO.initialize();
// Create a instance of Info represents a new info to be added
Info newInfo = new Info(new Integer(id));
newInfo.setInfoArea(infoArea);
newInfo.setInfoDate(Calendar.getInstance().getTime());
InfoDAO infoDao = new InfoDAO(); session s = _RootDAO.createSession();
Transaction tx = s.beginTransaction();
// Insert a empty value into info_cont first
newInfo.setInfoCont(Hibernate.createClob(" ") );
s.save(newInfo);
s.flush(); // Lock the relative row
s.refresh(newInfo, LockMode.UPGRADE);
CLOB clob = (CLOB) newInfo.getInfoCont();
java.io.Writer pw = clob.getCharacterOutputStream();
try {
pw.write(infoCont);// Write the CLOB value into table
pw.close();
} catch(IOException e) {
throw new HibernateException(e);
}
tx.commit();
s.close();不过这个方法是最笨的一个办法，更好的办法，或者说更透明的方法是通过实现net.sf.hibernate.UserType接口，来自定义处理oracle.CLOB类型的类。这种方法仍然在研究中：）。虽然说这个方法比较落后，但是，最起码现在可以通过hibernate插入oracle.CLOB字段了！
