Hibernate学习---第十二节：Hibernate之锁机制&乐观锁实现

package learn.hibernate.bean;

import java.util.Date;
import java.util.HashSet;
import java.util.Set;

/**
* 持久化类设计
* 注意：
*         持久化类通常建议要有一个持久化标识符(ID)
*         持久化标识符通常建议使用封装类(例如：Integer  因为基本类型存在默认值)
*         持久化类通常建议手动添加一个无参构造函数 (因为有些操作是通过放射机制进行的)
*         属性通常建议提供  getter/setter 方法
*         持久化类不能使用 final 修饰
*         持久化类中如果使用了集合类型数据，只能使用集合所对应的接口类型来声明(List/Map/Set)
*              如下：ArrayList list = new ArrayList();  不行
*                 List list = new ArrayList(); 可行
*/
public class Person {

private Integer id;
private String name;
private int age;
private int passwork;
private Date birthday;
private Integer version;

public Person() {

}

public Person(String name, int age, int passwork, Date birthday) {
super();
this.name = name;
this.age = age;
this.passwork = passwork;
this.birthday = birthday;
}

@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", age=" + age
+ ", passwork=" + passwork + ", birthday=" + birthday + "]";
}

public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getPasswork() {
return passwork;
}
public void setPasswork(int passwork) {
this.passwork = passwork;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}

public Integer getVersion() {
return version;
}

public void setVersion(Integer version) {
this.version = version;
}
}

<?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="learn.hibernate.bean">
<!--
optimistic-lock="version" 指定持久化类的乐观锁策略
-->
<class name="Person" table="t_person" optimistic-lock="version">
<id name="id" column="person_id">
<generator class="native"/>
</id>
<!-- 配置 锁字段和对应的属性关联，以及字段类型 -->
<version name="version" column="t_version" type="integer"/>
<property name="name" column="t_name"/>
<property name="age"/>
<property name="passwork"/>
<property name="birthday"/>
</class>
</hibernate-mapping>

/**
* hibernate 在获取数据的时候返回一个锁状态
* 在提交数据的时候会自动的将锁状态进行改变
*/
@Test
public void testUpdate(){
Person p1 = (Person)s1.get(Person.class, 1);
Person p2 = (Person)s2.get(Person.class, 1);

System.out.println("----------1---start-----------");
tx = s1.beginTransaction();
p1.setName("p1");
s1.update(p1);
tx.commit();
System.out.println("----------1---end-----------");

System.out.println("----------2---start-----------");
tx = s2.beginTransaction();
p2.setName("p2");
s2.update(p2);
tx.commit();
System.out.println("----------2---end-----------");
}