hibernate_05_单表操作_对象类型

本篇使用hibernate输出一个对象（图片）

先写一个java类

package com.imooc.hibernate;

import java.sql.Blob;
import java.util.Date;

public class Students {

    private int sid;
    private String sname;
    private String gender;
    private Date birthday;
    private String address;
    private Blob picture;
    
    public Blob getPicture() {
        return picture;
    }

    public void setPicture(Blob picture) {
        this.picture = picture;
    }

    public Students() {}

    public Students(int sid, String sname, String gender, Date birthday, String address) {
        super();
        this.sid = sid;
        this.sname = sname;
        this.gender = gender;
        this.birthday = birthday;
        this.address = address;
    }

    @Override
    public String toString() {
        return "Students [sid=" + sid + ", sname=" + sname + ", gender=" + gender + ", birthday=" + birthday
                + ", address=" + address + "]";
    }

    public int getSid() {
        return sid;
    }

    public void setSid(int sid) {
        this.sid = sid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

创建Students.hbm.xml文件

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2017-5-23 0:24:09 by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="com.imooc.hibernate.Students" table="STUDENTS">
        <id name="sid" type="int">
            <column name="SID" />
            <generator class="native" />
        </id>
        <property name="sname" type="java.lang.String">
            <column name="SNAME" />
        </property>
        <property name="gender" type="java.lang.String">
            <column name="GENDER" />
        </property>
        <property name="birthday" type="java.util.Date">
            <column name="BIRTHDAY" />
        </property>
        <property name="address" type="java.lang.String">
            <column name="ADDRESS" />
        </property>
        <property name="picture" type="java.sql.Blob">
            <column name="PICTURE" />
        </property>
    </class>
</hibernate-mapping>

创建hibernate.cfg.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="connection.username">root</property>
        <property name="connection.password">root</property>
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/hibernate?useUnicode=true&amp;characterEncoding=UTF-8</property>
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>
        <property name="hbm2ddl.auto">update</property>
        
        <mapping resource="com/imooc/hibernate/Students.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

创建测试类

package com.icoom.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.util.Date;

import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.imooc.hibernate.Students;

public class StudentsTest {
    
    private SessionFactory sessionFactory;
    private Session session;
    private Transaction transaction;

    @Before
    public void init() {
        // 1.创建配置对象
        Configuration config = new Configuration().configure();
        // 2.创建服务注册对象
        ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();
        // 3.创建会话工厂对象
        sessionFactory = config.buildSessionFactory(serviceRegistry);
        // 会话对象
        session = sessionFactory.openSession();
        // 开启事务
        transaction = session.beginTransaction();
    }
    @After
    public void destory() {
        transaction.commit(); //提交事务
        session.close(); //关闭session
        sessionFactory.close();//关闭会话工厂
    }

    
    /**
     * 使用hibernate输出对象
     * @throws Exception
     */
    @Test
    public void testReadBlob() throws Exception {
        Students s = (Students)session.get(Students.class, 1);// 获得id=1的学生对象
        // 获得Blob对象
        Blob image = s.getPicture();
        // 获得照片的输入流
        InputStream input = image.getBinaryStream();
        // 创建输出流
        File f = new File("d:" + File.separator + "out龙猫.jpg");
        // 获得输出流
        OutputStream output = new FileOutputStream(f);
        // 创建缓冲区
        byte[] buff = new byte[input.available()];
        input.read(buff);
        output.write(buff);
        input.close();
        output.close();
    }
}

执行成功，在D盘根目录中就会出现out龙猫.jpg文件。