Hibernate入门02_Session

1、 News.java与上一遍文章一样

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

public class News {
    private Integer id;
    private String title;
    private String author;
    private Date data;
    // 大文本
    private String content;
    // 二进制数据
    private Blob iamge;

    public News() {
        super();
    }

    public News(String title, String author, Date data) {
        super();
        this.title = title;
        this.author = author;
        this.data = data;
    }

    //get/set...

    @Override
    public String toString() {
        return "News [id=" + id + ", title=" + title + ", author=" + author + ", data=" + data + ", content=" + content
                + ", iamge=" + iamge + "]";
    }
}

News.hbm.xml

<?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 2017-3-24 17:22:48 by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping package="com.hibernate.entities">
    <class name="News" table="NEWS" dynamic-update="true">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="title" type="java.lang.String">
            <column name="TITLE" />
        </property>
        <property name="author" type="java.lang.String">
            <column name="AUTHOR" />
        </property>
        <property name="data" type="java.util.Date">
            <column name="DATA" />
        </property>
        <!-- 映射大对象 -->
        <property name="content" type="java.lang.String"></property>
        <property name="iamge" type="blob"></property>

    </class>
</hibernate-mapping>

2、Pay.java

public class Pay {
    private int monthlyPay;
    private int yearPay;
    private int vocationWithPay;
    private Worker worker;

    public Worker getWorker() {
        return worker;
    }
    public void setWorker(Worker worker) {
        this.worker = worker;
    }
    //get/set...
}

Pay.hbm.xml

<?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 2017-3-25 15:32:24 by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
    <class name="com.hibernate.entities.Pay" table="PAY">
        <id name="monthlyPay" type="int">
            <column name="MONTHLYPAY" />
            <generator class="assigned" />
        </id>
        <property name="yearPay" type="int">
            <column name="YEARPAY" />
        </property>
        <property name="vocationWithPay" type="int">
            <column name="VOCATIONWITHPAY" />
        </property>
    </class>
</hibernate-mapping>

3、Worker.java

import com.hibernate.entities.Pay;
public class Worker {
    private Integer id;
    private String name;
    private Pay pay;
    //get/set...
}

Worker.hbm.xml

<?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 2017-3-25 15:32:24 by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping package="com.hibernate.entities">
    <class name="Worker" table="WORKER">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <!-- 映射组成关系 -->
        <component name="pay" class="Pay">
            <parent name="worker" />
            <!-- 指定组成关系的组件的属性 -->
            <property name="monthlyPay" column="MONTHLY_PAY"></property>
            <property name="yearPay" column="YEAR_PAY"></property>
            <property name="vocationWithPay" column="VOCATION_WITH_PAY"></property>
        </component>
    </class>
</hibernate-mapping>

4、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>

    <!-- 配置链接数据库的基本信息 -->
        <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/hibernate01</property>

        <!-- hibernate的基本信息 -->
        <!-- hibernate使用的数据库方言 -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <!-- 执行操作时是否在控制台打印sql语句 -->
        <property name="show_sql">true</property>
        <!-- 是否对sql进行格式化 -->
        <property name="format_sql">true</property>
        <!-- 指定自动生成数据表的策略 -->
        <property name="hbm2ddl.auto">update</property>
        <!-- 设置hibernate的隔离级别 -->
        <property name="connection.isolation">2</property>
        <!-- 删除对象后，设置其OID为null -->
        <property name="use_identifier_rollback">true</property>

        <!-- 配置C3P0数据源 -->
        <property name="c3p0.max_size">100</property>
        <property name="c3p0.min_size">5</property>
        <property name="c3p0.acquire_increment">2</property>
        <property name="c3p0.idle_test_period">2000</property>
        <property name="c3p0.timeout">2000</property>
        <property name="c3p0.max_statements">10</property>

        <!-- 设置JDBC的statement读取数据库的时候每次从数据库中读取记录条数，这个值100合适，太大会损耗内存，小了速度慢 -->
        <property name="jdbc.fetch_size">100</property>
        <!-- 设置数据库进行批量删除，更新，插入的时候批次的大小，30比较合适 -->
        <property name="jdbc.batch_size">30</property>

        <!-- 指定关联的hbm.xml文件 -->
        <mapping resource="com/hibernate/entities/News.hbm.xml" />
        <mapping resource="com/hibernate/entities/Worker.hbm.xml" />
    </session-factory>
</hibernate-configuration>

5.Test

package com.hibernate;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Date;

import javax.xml.crypto.Data;

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

import com.hibernate.entities.News;
import com.hibernate.entities.Pay;
import com.hibernate.entities.Worker;

public class HibernateTest {

    private SessionFactory sessionFactory;
    private Session session;
    private Transaction transaction;

    @Test
    public void testComponent() {
        Worker worker = new Worker();
        worker.setName("name1");
        Pay pay = new Pay();
        pay.setMonthlyPay(7000);
        pay.setVocationWithPay(15);
        pay.setYearPay(100000);
        worker.setPay(pay);
        session.save(worker);
    }

    @Test
    public void testBlob() throws IOException, SQLException {
        // News news = new News();
        // news.setAuthor("AA");
        // news.setContent("BB");
        // news.setTitle("CC");
        // news.setData(new Date());
        // InputStream inputStream = new FileInputStream("timg.jpg");
        // Blob image = Hibernate.getLobCreator(session).createBlob(inputStream,
        // inputStream.available());
        // news.setIamge(image);
        // session.save(news);

        News news2 = (News) session.get(News.class, 32768);
        InputStream inputStream = news2.getIamge().getBinaryStream();
        System.out.println(inputStream.available());
    }

    @Test
    public void testDynamicUpdate() {
        News news = (News) session.get(News.class, 1);
        news.setAuthor("Oracle");
    }

    /** 调用原生的存储过过程 */
    @Test
    public void testDoWork() {
        session.doWork(new Work() {

            @Override
            public void execute(Connection connection) throws SQLException {
                System.out.println(connection);
                // 调用存储过程
            }
        });

    }

    /***
     * evict:把session缓存中的持久化对象移除
     */
    @Test
    public void testEvict() {
        News news = (News) session.get(News.class, 8);
        News news2 = (News) session.get(News.class, 9);
        news.setAuthor("EE");
        news2.setAuthor("FF");
        session.evict(news);

    }

    /***
     * 只要OID和数据库表中一条记录对应，就会删除该记录，若没有改记录就会抛出异常
     * 可以通过hibernate配置文件设置：use_identifier_rollback = true , 使删除对象后把其OID设为null
     */
    @Test
    public void testDelete() {
        // News news = new News();
        // news.setId(3);
        // session.delete(news);

        News news = (News) session.get(News.class, 7);
        session.delete(news);
        System.out.println(news);
    }

    /***
     * 若OID不为null，但数据表中没有对应的记录，会抛出一个StaleStateException
     * OID的值等于id的unsave-value属性值对象，也被认为是一个游离对象
     */
    @Test
    public void testSaveOrUpdate() {
        News news = new News("DD", "dd", new Date());
        news.setId(111);
        session.saveOrUpdate(news);

    }

    /***
     * 若更新一个持久化对象不需要显示调用upDate方法 更新一个游离对象需要显示调用,会吧一个游离对象转成持久对象
     * 
     * 需要注意： 1、无论要更新的游离对象和数据表是否一致，都会发生update语句
     * 不盲目update可以在。hbm.xml文件的class节点设置：select-berfore-update=true(默认false)，通常不需要设置，会多发一条select语句
     * 2、若数据表中没有对应的记录，update会抛出异常
     * 3、如果session缓存中已经存在相同OID的持久化对象，对抛出NonUniqueObjectException，因为在session缓存中不能有两个OID相同的对象
     * 
     */
    @Test
    public void testUpdate() {
        News news = (News) session.get(News.class, 1);
        transaction.commit();
        session.close();
        // news.setId(44);
        session = sessionFactory.openSession();
        transaction = session.beginTransaction();

        // news.setAuthor("Oralce");

        News news2 = (News) session.get(News.class, 1);
        session.update(news);

    }

    /***
     * get vs load: 1、get会立即加载对象（立即检索），load如不使用该对象，不会立即查询，而返回一个代理对象，（延迟检索）
     * 2、若数据库表中没有对应的数据，get()返回null，load()会发生异常
     * 3、load在session关闭后使用对象会抛出LazyInitializationException，懒加载异常
     */
    @Test
    public void testLoad() {
        News news = (News) session.load(News.class, 1);
        // session.close();
        System.out.println(news);

    }

    @Test
    public void testGet() {
        News news = (News) session.get(News.class, 1);
        // session.close();
        System.out.println(news);

    }

    /***
     * persist()也会发出insert操作
     * 与save()的区别：在persist()之前,若对象已经有id,不会执行insert(),而会抛出异常
     */
    @Test
    public void testPersist() {
        News news = new News();
        news.setAuthor("DD");
        news.setData(new Date());
        news.setTitle("dd");
        news.setId(200);
        session.persist(news);
    }

    @Test
    public void testSave() {
        News news = new News();
        news.setAuthor("AA");
        news.setData(new Date());
        news.setTitle("BB");
        System.out.println(news);
        // session.save(news);
        // System.out.println(news);
    }

    @Test
    public void testSessionCache() {

        // News news = (News) session.get(News.class, 1);
        // System.out.println(news);
        // News news2 = (News) session.get(News.class, 1);// 不会再一次发送查询语句
        // System.out.println(news2);

        News news = (News) session.get(News.class, 1);
        System.out.println(news);
        news.setAuthor("Sun");
        // session.flush();
        session.refresh(news);
        // session.clear();

        // News news2 = (News) session.get(News.class, 1);// 不会再一次发送查询语句
        System.out.println(news);
    }

    /***
     * 测试代码方法运行前执行
     */
    @Before
    public void init() {
        System.out.println("HibernateTest.init()");

        // 1.创建一个sessionFactory对象
        Configuration configuration = new Configuration().configure();
        ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())
                .buildServiceRegistry();
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);

        // 2.创建一个session对象
        session = sessionFactory.openSession();

        // 3.开启事务
        transaction = session.beginTransaction();

    }

    /***
     * 测试代码方法运行后执行
     */
    @After
    public void destroy() {
        System.out.println("HibernateTest.destroy()");
        // 5.提交事务
        transaction.commit();
        // 6.关闭session
        session.close();
        // 7.关闭SessionFactory
        sessionFactory.close();

    }

}

备注：本博客适合有一定java基础，对数据库有一定认识的读者。不会做过多的文字描述，敬请原谅。本人也是新手，写博客当做笔记作分享，不喜勿喷，欢迎指教。