使用Hibernate3来操作Clob字段的插入，修改，读取
1.实体类 1
2.映射文件 2
3.实体Form 3
4.Hibernate的Helper 3
5.Clob的插入 5
6.Clob的修改 5
7.Clob的读取 6
8.Clob的删除 6
项目中遇到要对Oralce数据库的CLOB字段进行处理的问题，即实现对CLOB值的插入，更新，查询。 Clob的的操作一般有三种方法：1。JDBC的方法。2：把clob当作String来处理。3.直接使用Clob。这里我介绍的是第三种方法。使用 Hibernate3 来管理数据库的连接session。
1.实体类
Entity实休类PublicInfo.Java结构如下,contentString为辅助字段，不映射到数据库中,这里注意的是映射到hbm.xml中的content字段的属性设type=”clob”就行了。
import java.io.Serializable;
import java.sql.Clob;
import java.util.Date;
/**
* @author ZhangWenRui
* @hibernate.class
*/
public class PublicInfo implements Serializable{
private Long id;
?? private String contentString;
?? private Clob content;//内容
/**
???? * @hibernate.id generator-class = "sequence" length = "16"
???? * @hibernate.generator-param name="sequence" value="seq_information"
???? * @return
???? */
??? public Long getId() {
??????? return id;
??? }
??? public void setId(Long id) {
??????? this.id = id;
??? }
/**
???? * @hibernate.property type="clob"
???? * @return
???? */
public Clob getContent() {
?? return content;
}
public void setContent(Clob content) {
?? this.content = content;
}
public String getContentString() {
?? return contentString;
}
}
2.映射文件
PublicInfo.hbm.xml映射文件如下：
<?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">
<hibernate-mapping>
??? <class
??????? name="com.eclink.publicinfo.entity.PublicInfo"
??????? table="publicInfo"
??? >
??????? <id
??????????? name="id"
??????????? column="id"
??????????? type="java.lang.Long"
??????????? length="16"
??????? >
??????????? <generator include-all = "true"
* @author ZhangWenRui
*
*/
public class PublicInfoForm extends ValidatorForm{
private String contentString;
public String getContentString() {
?? return contentString;
}
public void setContentString(String contentString) {
?? this.contentString = contentString;
}
}
4.Hibernate的Helper
hibernate.cfg.xml放置于/WEB-INF/hibernate.cfg.xml下。
HibernateUtils用于管理Hibernate的sessionfactory.
import org.hibernate.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
/**
* @author ZhangWenRui
*/
public class HibernateUtils {
private static SessionFactory sessionFactory;
static Configuration configuration = new Configuration().configure("../hibernate.cfg.xml");
static{
?? try {
??? sessionFactory = configuration.buildSessionFactory();
?? } catch (Throwable e) {
??? System.out.println("create sessionFactory failed!");
?? }
}
public static SessionFactory getSessionFactory(){
?? return sessionFactory;
}
public static void initialize(Object proxy) {
?? if (proxy != null){??
?? try {
??? Hibernate.initialize(proxy);
?? } catch (HibernateException e) {
??? throw new RuntimeException("Can't initialize hibernate proxy", e);
?? }
?? }
}
}
hibernate.cfg.xml内容如下：
<?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">
<hibernate-configuration>
<session-factory>
?? <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
?? <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
?? <property name="hibernate.connection.url">jdbc:oracle:thin:@192.168.0.2:1521:info</property>
?? <property name="hibernate.connection.username">info</property>
?? <property name="hibernate.connection.password">info</property>
?? <property name="hibernate.connection.pool_size">10</property>
?? <property name="show_sql">true</property>
?? <property name="use_outer_join">true</property>
?? <property name="hibernate.jdbc.batch_size">20</property>
??
?? <mapping resource="com/publicinfo/entity/PublicInfo.hbm.xml" />
</session-factory>
</hibernate-configuration>
5.Clob的插入
public void addPublicInfo(PublicInfo publicInfo) throws SQLException, IOException {
?? org.hibernate.Session session = HibernateUtils.getSessionFactory().openSession();//建立一个session
?? Transaction tx = session.beginTransaction();//事务
?? publicInfo.setContent(Hibernate.createClob(" "));//插入空的clob值
?? session.save(publicInfo);
?? session.flush();
?? session.refresh(publicInfo, LockMode.UPGRADE);//锁定
?? org.hibernate.lob.SerializableClob cb = (org.hibernate.lob.SerializableClob) publicInfo.getContent();
?? java.sql.Clob wrapClob = (java.sql.Clob) cb.getWrappedClob();
?? if(wrapClob instanceof oracle.sql.CLOB){
??? oracle.sql.CLOB clob = (oracle.sql.CLOB) wrapClob;
??? java.io.Writer writer = clob.getCharacterOutputStream();
??? String contentStr = publicInfo.getContentString();
??? writer.write(contentStr);
??? writer.close();
?? }
?? tx.commit();
?? session.close();
}
?
6.Clob的修改
public void updatePublicInfo(PublicInfo publicInfo) throws SQLException, IOException {
?? Session session = HibernateUtils.getSessionFactory().openSession();
?? Transaction tx = session.beginTransaction();
?? publicInfo.setContent(Hibernate.createClob(" "));
?? session.saveOrUpdate(publicInfo);
?? session.flush();
?? session.refresh(publicInfo, LockMode.UPGRADE);
?? SerializableClob cb = (SerializableClob) publicInfo.getContent();
?? Clob wrapClob = (Clob) cb.getWrappedClob();
?? if(wrapClob instanceof CLOB){
??? CLOB clob = (CLOB) wrapClob;
??? Writer writer = clob.getCharacterOutputStream();
??? String contentStr = publicInfo.getContentString();
??? writer.write(contentStr);
??? writer.close();
?? }
?? tx.commit();
?? session.close();
}
7.Clob的读取
Clob clob = publicInfo.getContent();
?? String contentStr = "";
?? if(clob != null)
??? contentStr = clob.getSubString(1, (int)clob.length());
8.Clob的删除
由于删除操作不需要对Clob类型作特殊处理，只要通过id找出相应的实体删掉就行。
