Hibernate入门_增删改查

一、Hibernate入门案例剖析：

　　 ①创建实体类Student 并重写toString方法

public class Student {

    private Integer sid;

    private Integer age;

    private String name;

    public Integer getSid() {

        return sid;

    }

    public void setSid(Integer sid) {

        this.sid = sid;

    }

    public Integer getAge() {

        return age;

    }

    public void setAge(Integer age) {

        this.age = age;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    @Override

    public String toString() {

        return "Student [sid=" + sid + ", age=" + age + ", name=" + name + "]";

    }

}

　　② 创建学生对象并赋值

　③引入jar包

④ 构建大配置<hibernate.cfg.xml>

可分为以下步骤：

1.连接数据库的语句

2.sql方言

3.可省的配置(show_sql、format_sql 取值为true)

4.让程序生成底层数据表(hbm2ddl.auto) update/create。create是每次将数据表删除后，重新创建

5.关联小配置

关键代码如下：

<?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>

        <!-- Database connection settings 数据库连接设置-->

        <!-- 驱动类 -->

        <property name="connection.driver_class">oracle.jdbc.OracleDriver</property>

        <!-- url地址 -->

        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl3</property>

        <property name="connection.username">wj</property>

        <property name="connection.password">9090</property>

        <!-- SQL dialect  (SQL 方言) -->

        <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>

        <!--在控制台打印后台的SQL语句 -->

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

        <!-- 格式化显示SQL -->

        <!-- <property name="format_sql">true</property> -->

        <!-- 自动生成student表 -->

         <property name="hbm2ddl.auto">update</property>

        <!-- 关联小配置 -->

        <mapping resource="cn/happy/entity/Student.hbm.xml" />

        <!-- <mapping class="cn.happy.entity.Grade"/> -->

    </session-factory>

</hibernate-configuration>

⑤ 构建小配置(Student.hbm.xml)

<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="cn.happy.entity">

        <class name="Student" table="STUDENT">

        <id name="sid" column="SID">

           <!-- 主键生成策略：native:

           native:如果后台是Oracle

                               后台是MySQL，自动应用自增

              assigned:程序员给主键赋值

              uuid:32位的16进制数

              sequence

              native

            -->

            <generator class="assigned">

               <param name="sequence">SEQ_NUM</param>

            </generator>

        </id>

       <!--  <version name="version"></version> -->

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

        <property name="age"/>

    </class>

</hibernate-mapping>

⑥ 工具类HibernateUtil、构建私有静态的Configuration、SessionFactory对象、定义返回session以及关闭session的方法

private static Configuration cf=new Configuration().configure();

    private static SessionFactory sf=cf.buildSessionFactory();

    //方法返回session

    public static Session getSession(){

        return sf.openSession();

    }

    //关闭Session

    public static void CloseSession(){

        getSession().close();

    }

复制代码

⑦测试类【增删改查】使用标记After、Before可简化代码

package cn.happy.test;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

import cn.happy.entity.Student;

import cn.happy.util.HibernateUtil;

public class Test1 {

    Session session;

    Transaction tx; 

    @After

    public void afterTest(){

        tx.commit();

        HibernateUtil.CloseSession();

    }

    @Before

    public void initData(){

        session=HibernateUtil.getSession();

        tx=session.beginTransaction();

    }

    /*

     * get方法查询

     */

    @Test

    public void getData(){

        Student stu=(Student)session.get(Student.class, 3);

        System.out.println(stu);

    }

    /*

     * 增加

     */

    @Test

    public void addData(){

        Student stu=new Student();

        stu.setSid(12);

        stu.setAge(11);

        stu.setName("李小龙1");

    //读取大配置文件 获取连接信息

        Configuration cfg=new Configuration().configure();

    //创建SessionFactory

        SessionFactory fa=cfg.buildSessionFactory();

    //加工Session

    Session se=fa.openSession();

    Transaction tx = se.beginTransaction();

    //保存

    se.save(stu);

    //事务提交

    tx.commit();

    se.close();

    System.out.println("Save ok!");

    }

    /*

     * 删除

     */

    @Test

    public void delData(){

        Session session=HibernateUtil.getSession();

        Student stu=new Student();

        stu.setSid(2);

        Transaction tx=session.beginTransaction();

        session.delete(stu);

        tx.commit();

        HibernateUtil.CloseSession();

        System.out.println("del ok!");

    }

    /*

     * 修改

     */

    @Test

    public void updateData(){

        Session session=HibernateUtil.getSession();

        Student stu=(Student)session.load(Student.class,3);

        stu.setName("呵呵");

        Transaction tx=session.beginTransaction();

        session.update(stu);

        tx.commit();

        HibernateUtil.CloseSession();

        System.out.println("update ok!");

    }

    }

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Hibernate入门_增删改查

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