Hibernate中LockMode 在oracle9i中的效果

LockMode
   int level;
   String name;
锁的级别: 
  NONE:0
  READ:5
  UPGRADE:10
  UPGRADE_NOWAIT:10
  WRITE:10
  FORCE:15

notice:WRITE lock is not a valid mode for load() or lock()
如果使用的是oracle9i数据库则,相应的锁所产生的SQL语句如下:

Method:   session.load():
  LockMode.UPGRADE_NOWAIT   
    for update nowait
  LockMode.UPTRADE
    for update
  LockMode.WRITE
    an exception occur 
  LockMode.READ
    as none 

Method:   query.setLockMode():
    LockMode.UPGRADE
        for update of echoinfo0_.ID
    LockMode.UPGRADE_NOWAIT   
        for update of echoinfo0_.ID nowait
    LockMode.WAIT
       for update of echoinfo0_.ID
    LoclMode.READ 

这里提供一个程序实现的样例:

 

  java 代码
 
 
/*
 * Created on 2007-5-17
 */
package com.snow.hib.oracle;

import org.hibernate.*;
import org.hibernate.LockMode;

/**
 *@author anwxAn Weixiao
 *@version $Id$
 */
public class Test {
    private static final Session session = HibernateUtil.currentSession();

    /**
     * demo method one
     * @param id
     * @return
     */
    public EchoInfo findEchoInfo(String id) {
        /*
         * select
         *     echoinfo0_.ID as ID0_0_,
         *     echoinfo0_.MESSAGE as MESSAGE0_0_
         *  from
         *     Echo_Info_anwx echoinfo0_
         *  where
         *     echoinfo0_.ID=?
         *  LockMode.UPGRADE_NOWAIT
         *     for update nowait
         *  LockMode.UPTRADE
         *     for update
         *  LockMode.WRITE
         *     an exception occur
         *  LockMode.READ
         *     as none
         */
        EchoInfo info = (EchoInfo) session.load(EchoInfo.class, "123456",
                LockMode.READ);
        return info;
    }

    /**
     * demo method two
     *
     */
    public static void getCounts() {
        /*
         * select
         *     echoinfo0_.ID as ID0_0_,
         *     echoinfo0_.MESSAGE as MESSAGE0_0_
         *  from
         *     Echo_Info_anwx echoinfo0_
         *     --下面是使用不同级别的锁所产生的不同的SQL in oracle9i
         *     LockMode.UPGRADE
         *        for update of echoinfo0_.ID
         *     LockMode.UPGRADE_NOWAIT
         *        for update of echoinfo0_.ID nowait
         *     LockMode.WAIT
         *        for update of echoinfo0_.ID
         *     LoclMode.READ
         *
         */
        int counts = 0;
        try {
            Query query = session.createQuery("from EchoInfo m");
            query.setLockMode("m", LockMode.WRITE);
            counts = query.list().size();
        } catch (HibernateException e) {
            System.out.println("error occur");
        }
        System.out.println("counts:" + counts);
    }

    public static void main(String[] args) {
        Test test = new Test();
              System.out.println("Start.");
              EchoInfo info=test.findEchoInfo("123456");
              System.out.println("ID: "+info.getId());
              System.out.println("Message:"+info.getMessage());
        getCounts();
        session.close();
    }
}