Hibernate文件配置

ORM : 對象關系映射

映射需要通過XML的配置文件來完成，這個配置文件盡量統一（xxx.hbm.xml） Hibernate核心的配置：必須的配置、可選的配置、映射文件的引入

Configuration的作用：1.加載核心配置文件 2.加載映射文件 SessionFactory：內部維護了Hibernate的連接池和Hibernate的二級緩存，是線程安全的對象，一個項目創建一個對象即可 Session：代表Hibernate和數據庫的連接對象，不是線程安全的，所以不能定義成全局的變量 Transaction：Hibernate中管理事務的對象

文件結構

工具類

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

public class HibernateUtils {
    public static final Configuration cfg;
    public static final SessionFactory sf;

    static {
        cfg = new Configuration().configure();
        sf = cfg.buildSessionFactory();
    }

    public static Session openSession() {
        return sf.openSession();
    }
}

對象類

public class Customer {
    private int id;
    private String name;
    private String source;
    private String industry;
    private String level;
    private String phone;
    private String mobile;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSource() {
        return source;
    }

    public void setSource(String source) {
        this.source = source;
    }

    public String getIndustry() {
        return industry;
    }

    public void setIndustry(String industry) {
        this.industry = industry;
    }

    public String getLevel() {
        return level;
    }

    public void setLevel(String level) {
        this.level = level;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getMobile() {
        return mobile;
    }

    public void setMobile(String mobile) {
        this.mobile = mobile;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", source='" + source + '\'' +
                ", industry='" + industry + '\'' +
                ", level='" + level + '\'' +
                ", phone='" + phone + '\'' +
                ", mobile='" + mobile + '\'' +
                '}';
    }
}

映射配置文件

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <!--建立類與表的映射-->
    <!--如果類中的屬性名和表中的字段名一直，column可以省略-->
    <class name="com.jinke.hibernate.Customer" table="customer">
        <!--建立類中的屬性與表中的主鍵對應-->
        <id name="id" column="id">
            <generator class="native"/>
        </id>

        <!--建立類中的普通屬性和標的字段的對應-->
        <property name="name" column="name" length="32" type="string" not-null="true" unique="true"/>
        <property name="source" column="source"/>
        <property name="industry" column="industry"/>
        <property name="level" column="level"/>
        <property name="phone" column="phone"/>
        <property name="mobile" column="mobile"/>
    </class>
</hibernate-mapping>

總配置類

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!--必須配置===============-->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/spring_database?characterEncoding=utf8
        </property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">1234</property>
        <!--配置Hibernate的方言-->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <!--可選配置===============-->
        <!--打印sql-->
        <property name="hibernate.show_sql">true</property>
        <!--格式化sql-->
        <property name="hibernate.format_sql">true</property>
        <!--自動創建表-->
        <property name="hibernate.hbm2ddl.auto">update</property>

        <!--映射文件的引用===============-->
        <mapping resource="com/jinke/hibernate/Customer.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

測試類

import com.jinke.hibernate.utils.HibernateUtils;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.query.NativeQuery;
import org.hibernate.query.Query;
import org.junit.Test;

import java.util.Arrays;
import java.util.List;

public class HibernateDemo1 {

    @Test
    public void demo() {
       /* //1.加載hibernate核心配置文件
        Configuration configuration = new Configuration().configure();
        //2.創建一個sessionfactory對象：類似于jdbc中連接池
        SessionFactory sessionFactory = configuration.buildSessionFactory();
        //3.通過sessionFactory獲取到session對象：類似于jdbc中connection
        Session session = sessionFactory.openSession();*/

        Session session = HibernateUtils.openSession();
        //4.手動開啟事務
        Transaction transaction = session.beginTransaction();
        //5.編寫代碼

        Customer customer = new Customer();
        customer.setName("王東");
        //保存
        session.save(customer);


        //6.事務提交
        transaction.commit();
        //7.資源釋放
        session.close();
        /*sessionFactory.close();*/
    }

    /**
     * get方法：（一般用這種）
     * 采用立即加載，執行到這行代碼的時候，馬上發送SQL語句去查詢
     * 查詢后返回的是真是對象本身
     * 查詢一個找不到的對象會返回null
     * <p>
     * load方法：
     * 采用延遲加載（懶加載），執行到這行代碼的時候，不會發送SQL語句，當真正使用項目的時候才會發送SQL語句
     * 查詢后返回的是代理對象
     * 查詢一個找不到的對象會拋出一個異常
     */
    @Test
    //查詢
    public void demo2() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //使用get方法
        Customer customer = session.get(Customer.class, 1);
        System.out.println(customer);

        //使用load方法
        /*Customer load = session.load(Customer.class, 2);
        System.out.println(load);*/

        tx.commit();
        session.close();
    }

    @Test
    //修改
    public void demo3() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();

        //直接創建對象，進行修改
        /*Customer customer = new Customer();
        customer.setId(1);
        customer.setName("李達");
        session.update(customer);*/
        //先查詢，再修改（一般用這種）
        Customer customer = session.get(Customer.class, 1);
        customer.setName("張三");
        session.update(customer);

        tx.commit();
        session.close();
    }

    @Test
    //刪除
    public void demo4() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();

        //直接創建對象，進行刪除
        /*Customer customer = new Customer();
        customer.setId(1);
        session.delete(customer);*/
        //先查詢，再刪除(一般用這種)  級聯刪除
        Customer customer = session.get(Customer.class, 1);
        session.delete(customer);

        tx.commit();
        session.close();
    }

    @Test
    //保存或更新
    public void demo5() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();

        Customer customer = new Customer();
        /*customer.setName("李飛");
        session.saveOrUpdate(customer);*/

        customer.setId(3);
        customer.setName("如花");
        session.saveOrUpdate(customer);

        tx.commit();
        session.close();
    }

    @Test
    //查詢所有
    public void demo6() {
        Session session = HibernateUtils.openSession();
        Transaction tx = session.beginTransaction();
        //接收HQL：hibernate query language 面向對象的查詢語言
        Query query = session.createQuery("from Customer");
        List<Customer> list = query.list();
        for (Customer customer : list) {
            System.out.println(customer);
        }

        //接收sql：
        NativeQuery sqlQuery = session.createSQLQuery("select * from customer");
        List<Object[]> sqlList = sqlQuery.list();
        for (Object[] objects : sqlList) {
            System.out.println(Arrays.toString(objects));
        }

        tx.commit();
        session.close();
    }
}

結果在MySql Workbench里看