Hibernate对BLOB CLOB操作

create table users
(
 uids int primary key,
 img blob,
 txt clob
)

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Writer;
import java.sql.Clob;
import java.sql.SQLException;
import java.util.List;

import oracle.sql.CLOB;

import org.hibernate.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.lob.SerializableBlob;
import org.hibernate.lob.SerializableClob;

import com.yl.hibernater.bean.Users;

/**
 * Hibernate3.1+classes12.jar(oracle)
 * 
 * 我的想法是：在oracle中创建一张表包含BLOB,CLOB字段。刚开始这样做的。
 * 后来跟Hibernate映射的时候*.hbm.xml文件中老是默认的创建了复合主键，网上查了，映射的时候必须要一个主键字段。
 * 
 * 说明下 POJO 与 xml 文件中的数据类型都是java.sql.Blob与java.sql.Clob
 * BLOB放图片
 * CLOB放大型文本
 * 
 * 在做这个例子的时候，类型的转化真的有点晕。 呵呵
 * 
 * @author YouLong
 * @date 2009.6.18
 */
public class Text 
{
	@SuppressWarnings("unchecked")
	public static void main(String[] args)
	{
		Configuration hf = HibernateSessionFactory.getConfiguration(); 
		SessionFactory hsf =  hf.buildSessionFactory();
		Session session = hsf.openSession();
		Transaction ta = session.beginTransaction();
		try 
		{
			Users u = new Users();
			u.setUids(1);
			u.setImg(Hibernate.createBlob(new byte[1]));	//这里相当于在内存添加的默认值
			u.setTxt(Hibernate.createClob(new String("1")));//这里相当于在内存添加的默认值
			session.save(u);//保存不提交
			session.flush();//强制执行insert
			session.refresh(u,LockMode.UPGRADE); //给表上锁

			//开始读文件内容，并写入BLOB字段
			FileInputStream fis = new FileInputStream("E:\\workspace\\YL\\src\\com\\yl\\socket\\blogjava\\output.jpg");
			SerializableBlob bb = (SerializableBlob) u.getImg(); // 先从java.sql.Blob转SerializableBlob
			java.sql.Blob blob = bb.getWrappedBlob(); //再从通过getWrappedBlob()这个方法又转为java.sql.Blob，这里实在不理解
			if(blob instanceof oracle.sql.BLOB)//判断类型
			{
				oracle.sql.BLOB ob = (oracle.sql.BLOB)blob;// 从java.sql.Blob转oracle.sql.BLOB
				OutputStream writer = ob.getBinaryOutputStream();
				byte [] b = new byte[102400];
				int len = 0;
				while((len=fis.read(b))!=-1)
				{
					writer.write(b, 0, len);
				}
				fis.close();
				writer.close();
			}
			
			//开始读文件内容，并写入CLOB字段
			SerializableClob sclob = (SerializableClob) u.getTxt();
			Clob clob = sclob.getWrappedClob();
			if(clob instanceof oracle.sql.CLOB)
			{
				oracle.sql.CLOB cc = (CLOB) clob;
				Writer w = cc.getCharacterOutputStream();
				w.write("YOULONG IS GOOD!!");
				w.close();
			}
			
			ta.commit();//向数据库提交事务,再查询
			
			Query query = session.createQuery("from Users");
			List<Users> list = query.list();
			for (int i = 0; i < list.size(); i++) 
			{
				Users us = (Users)list.get(i);
				SerializableBlob ub = (SerializableBlob) us.getImg();
				java.sql.Blob ib = ub.getWrappedBlob();
				if(ib instanceof oracle.sql.BLOB)
				{
					InputStream in = ib.getBinaryStream();
					FileOutputStream fos = new FileOutputStream("c:/a.jpg"); //向外面生成图片
					byte [] by = new byte[102400];
					int j = 0;
					while((j=in.read(by))!=-1)
					{
						fos.write(by, 0, j);
					}
					in.close();
					fos.close();
				}
				
				SerializableClob sb = (SerializableClob)us.getTxt();
				java.sql.Clob ic = sb.getWrappedClob();
				if(ic instanceof oracle.sql.CLOB)
				{
					oracle.sql.CLOB cb = (oracle.sql.CLOB)ic;
					System.out.println(cb.getSubString(1, (int) cb.length()));
				}
			}
		} catch (HibernateException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally{
			session.close();
		}
	}
}

评论

1 楼 hehaiztc 2010-04-21  

不错，写的很好，对我帮助很大！