Hibernate读写Clob和Blob类型字段

最新推荐文章于 2021-03-04 10:23:42 发布

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#Hibernate #Java #MySQL #SQL #Myeclipse

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本文介绍了一个使用Hibernate框架操作数据库Blob与Clob类型的完整案例，包括创建表、配置文件、POJO类定义、XML映射文件及测试代码。通过这个实例，读者可以了解如何在Java应用程序中存储和读取图片及文本等大数据对象。

来自：http://esffor.iteye.com/blog/168264

数据库脚本：

create table testcb(id varchar ( 32 ) primary key ,name varchar ( 32 ),photo blob,description text );

Hibernate.cfg.xml

<? 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 ="connection.username" > root </ property >

< property name ="connection.url" >

jdbc:mysql://localhost:3306/schoolproject?characterEncoding=gb2312 & useUnicode=true

</ property >

< property name ="dialect" >

org.hibernate.dialect.MySQLDialect

</ property >

< property name ="myeclipse.connection.profile" > mysql </ property >

< property name ="connection.password" > 1234 </ property >

< property name ="connection.driver_class" >

com.mysql.jdbc.Driver

</ property >

< property name ="hibernate.dialect" >

org.hibernate.dialect.MySQLDialect

</ property >

< property name ="hibernate.show_sql" > true </ property >

< property name ="current_session_context_class" > thread </ property >

< mapping resource ="Search/Clob_Blob/TestCB.hbm.xml" />

</ session-factory >

</ hibernate-configuration >

POJO：

package Search.Clob_Blob;

import java.sql.Blob;

import java.sql.Clob;

public class TestCB ... {

private String id; // 标识id

private String name; // 学生姓名

private Blob photo;

private Clob description;

public String getId() ... {

return id;

}

public void setId(String id) ... {

this .id = id;

}

public String getName() ... {

return name;

}

public void setName(String name) ... {

this .name = name;

}

public Blob getPhoto() ... {

return photo;

}

public void setPhoto(Blob photo) ... {

this .photo = photo;

}

public Clob getDescription() ... {

return description;

}

public void setDescription(Clob description) ... {

this .description = description;

}

TestCB.hbm.xml

<? 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" >

<!--

Mapping file autogenerated by MyEclipse - Hibernate Tools

-->

< hibernate-mapping package ="Search.fetch" >

< class name ="Search.Clob_Blob.TestCB" table ="testcb" lazy ="true" >

< id name ="id" column ="id" unsaved-value ="null" >

< generator class ="uuid.hex" ></ generator >

</ id >

< property name ="name" column ="name" type ="string" ></ property >

< property name ="photo" column ="photo" type ="blob" ></ property >

< property name ="description" column ="description" type ="clob" ></ property >

</ class >

</ hibernate-mapping >

准备一个图片sample.jpg放在Clob_Blob包下

写Blob和Clob测试代码：

package Search.Clob_Blob;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.sql.Blob;

import java.sql.Clob;

import org.hibernate.Hibernate;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

public class Test ... {

public static void main(String[] args) ... {

String filePath = System.getProperty( " user.dir " ) + File.separator + " src/Search/Clob_Blob " + File.separator + " hibernate.cfg.xml " ;

File file = new File(filePath);

SessionFactory sessionFactory = new Configuration().configure(file).buildSessionFactory();

Session session = sessionFactory.openSession();

Transaction tx = session.beginTransaction();

try ... {

String imgPath = System.getProperty( " user.dir " ) + File.separator + " src/Search/Clob_Blob " + File.separator + " sample.jpg " ;

FileInputStream fis = new FileInputStream(imgPath);

Blob photo = Hibernate.createBlob(fis);

Clob description = Hibernate.createClob( " this is description " );

TestCB testcb = new TestCB();

testcb.setName( " tom1 " );

testcb.setPhoto(photo);

testcb.setDescription(description);

session.save(testcb);

tx.commit();

} catch (FileNotFoundException e) ... {

e.printStackTrace();

} catch (IOException e) ... {

e.printStackTrace();

}

、

运行后，在mysql客户端中可以看到已经成功保存：

运行读取测试代码：

package Search.Clob_Blob;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.SQLException;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class TestRead ... {

     public static void main(String[] args) ... {
        String filePath = System.getProperty( " user.dir " ) + File.separator + " src/Search/Clob_Blob " + File.separator + " hibernate.cfg.xml " ;
        File file = new File(filePath);
        SessionFactory sessionFactory = new Configuration().configure(file).buildSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction tx = session.beginTransaction();

         // 读取clob和blob
        String imgPath = System.getProperty( " user.dir "