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

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

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!");
}
}