Hibernate操作Clob类型数据

在POJO中字符串大对象可以声明成一个java.lang.String或java.sql.Clob类型。

当程序从数据库中加载Clob类型数据时，仅仅加载了一个Clob类型的数据的逻辑指针。我们需要通过使用Clob.getCaracterStream()方法得到Clob类型的数据输入流之后才能获取大对象数据。

看下面具体代码

package dao;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.math.BigDecimal;
import java.sql.Clob;
import java.sql.SQLException;

import org.hibernate.LobHelper;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import entity.Clobtable;
import Factory.HibernateSessionFactory;

public class ClobDao {
	private Session session = null;
	private Transaction tran = null;
	public ClobDao() {
		session = HibernateSessionFactory.getSession();
	}
	
	
	public void saveClob(BigDecimal id,String content){
		Clobtable ct = new Clobtable();
		ct.setId(id);
		LobHelper lh = session.getLobHelper();
		ct.setContent(lh.createClob(content));
		tran = session.beginTransaction();
		try{
			session.save(ct);
			tran.commit();
			System.out.println("插入成功！");
		}catch(Exception e){
			tran.rollback();
			System.out.println("插入失败");
		}
	}
	
	public void getClob(BigDecimal id){
		String hql = "from Clobtable where id = ?";
		Query query = session.createQuery(hql);
		query.setBigDecimal(0, id);
		Clobtable ct = (Clobtable) query.uniqueResult();
		Clob clob = ct.getContent();
		try {
			Reader reader = clob.getCharacterStream();
			BufferedReader br = new BufferedReader(reader);
			String content = br.readLine();
			System.out.println(content);
		} catch (SQLException e) {
			e.printStackTrace();
			System.out.println("读取失败！");
		} catch (IOException e) {
			System.out.println("读取失败！");
		}
		
	}
}