使用spring的annotation配置事务
首先配置Hibernate的局部事务管理，使用HibernateTransactionManager类，该类实现了PlatformTransactionManager接口，是针对Hibernate的特定实现，如下添加：

    <bean id="transactionManager"            ref="sessionFactory"></property>    </bean>

另外需要开启annotation支持，添加如下配置：

<tx:annotation-driven transaction-manager="transactionManager"/>

添加完成后我的applicationContext.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?><beans    xmlns="http://www.springframework.org/schema/beans"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns:aop="http://www.springframework.org/schema/aop"    xmlns:p="http://www.springframework.org/schema/p"    xmlns:context="http://www.springframework.org/schema/context"    xmlns:tx="http://www.springframework.org/schema/tx"    xsi:schemaLocation="http://www.springframework.org/schema/beans     http://www.springframework.org/schema/beans/spring-beans-2.0.xsd    http://www.springframework.org/schema/aop     http://www.springframework.org/schema/aop/spring-aop-2.0.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context-3.0.xsd    http://www.springframework.org/schema/tx    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">    <!-- derby创建用户名和密码参考：http://www.joyzhong.com/archives/643 -->    <bean        id="dataSource"        ref="sessionFactory"></property>    </bean>    <tx:annotation-driven transaction-manager="transactionManager"/></beans>

使用事务时，只需要在某方法上使用@Transactional标注即可，例如：

@Service("accountService")public class AccountServiceImpl implements AccountService {@Autowiredprivate AccountDao accountDao;@Autowiredprivate BookDao bookDao;public AccountDao getAccountDao() {return accountDao;}public void setAccountDao(AccountDao accountDao) {this.accountDao = accountDao;}public BookDao getBookDao() {return bookDao;}public void setBookDao(BookDao bookDao) {this.bookDao = bookDao;}@Overridepublic Account getAccountByUserID(int user_id) {Account account = this.accountDao.getAccountByUserID(user_id);return account;}@Transactional@Overridepublic void buyBooks(Account account, Book book, int num) {account.setBalance(account.getBalance() - book.getPrice()*num);book.setAmount(book.getAmount() - num);this.bookDao.update(book);this.accountDao.update(account);}}

上面的buyBooks模拟了一次购买书的过程，在这次购书过程中需要两次与数据库交互，首先调用bookDao的update方法减少书的数量，然后调用accountDao的update方法减少账户余额。如果该过程不采用事务，假设某一次买书的过程中书的数量是充足的，而账户的余额不足，那么就会出现书的数量减少了而余额却仍是原来的余额，这肯定出问题。加上事务之后就不会出现了上面的问题了，如果这次执行中出现了异常，那么事务的全部操作都被回滚。