悲观锁 HibernateTest.java

HibernateTest.java

代码：

/**  *  */ package com.b510.examplex;

import java.util.List;

import org.hibernate.LockMode; import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.Transaction;

/**  *  * @author XHW  *  * @date 2011-7-8  *  */ public class HibernateTest {

 /**   * @param args   */  public static void main(String[] args) {   HibernateTest test = new HibernateTest();   test.testLockMode();  }

 public void testLockMode() {   Session session = HibernateSessionFactoryUtil.getSessionFactory()     .openSession();   session.beginTransaction();   Query query=session.createQuery("from Guestbook gb");  //设置为“悲观锁”   悲观地认为每次读读取或修改数据库数据时，其他的事务也在并发访问相同的数据          <具有很强的排他性>   query.setLockMode("gb", LockMode.UPGRADE);   List<Guestbook> list=query.list();   session.getTransaction().commit();   for(Guestbook gb:list){    System.out.println(gb.getId());    System.out.println(gb.getName());    System.out.println(gb.getTitle());    System.out.println(gb.getEmail());   }  }

}

运行效果：

没有加“悲观锁”的效果：

sql语句：

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment). log4j:WARN Please initialize the log4j system properly. Hibernate:    select         guestbook0_.id as id2_,         guestbook0_.name as name2_,         guestbook0_.email as email2_,         guestbook0_.phone as phone2_,         guestbook0_.title as title2_,         guestbook0_.content as content2_,         guestbook0_.created_time as created7_2_     from         users.guestbook guestbook0_ 1 Hongten hello world! hongtenzone@foxmail.com

现在加入“悲观锁”

sql语句：

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment). log4j:WARN Please initialize the log4j system properly. Hibernate:     select         guestbook0_.id as id2_,         guestbook0_.name as name2_,         guestbook0_.email as email2_,         guestbook0_.phone as phone2_,         guestbook0_.title as title2_,         guestbook0_.content as content2_,         guestbook0_.created_time as created7_2_     from         users.guestbook guestbook0_ for update 1 Hongten hello world! hongtenzone@foxmail.com