package com.laola.dao;public interface BookShopDao {    //通过编号查询书的价格public int findBookPriceByIsbn(String Isbn);//通过编号查询书的库存public void updateBookStock(String Isbn);//通过名字查余额public void updateBalance(String username,int price);
}

package com.laola.dao;import java.util.List;public interface Cashier {void checkout(String username, List<String> isbns);
}

package com.laola.Impl;import com.laola.dao.BookShopDao;
import com.laola.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;//@Transactional （这里定义一个事务。注：如果不想配置XML文件可以用这些注解）
//@Service
public class BookServiceImpl implements BookService {//@Autowiredprivate BookShopDao bookShopDao;public void setBookShopDao(BookShopDao bookShopDao) {this.bookShopDao = bookShopDao;}@Overridepublic void purchase(String username, String Isbn) {            //获取价格int price=bookShopDao.findBookPriceByIsbn(Isbn);            //更新库存bookShopDao.updateBookStock(Isbn);            //更新余额bookShopDao.updateBalance(username,price);}
}

package com.laola.Impl;import com.laola.dao.BookShopDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;//@Repository("bookShopDao")
public class BookShopDaoImpl  implements BookShopDao {//@Autowiredprivate JdbcTemplate jdbcTemplate;public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {this.jdbcTemplate = jdbcTemplate;}//实现价格查询@Overridepublic int findBookPriceByIsbn(String isbn) {String sql="select price from book where Isbn = ?";return jdbcTemplate.queryForObject(sql,Integer.class,isbn);}//实现库存更新@Overridepublic void updateBookStock(String isbn) {String sql2="select stock from stock where Isbn = ?";Integer stock = jdbcTemplate.queryForObject(sql2, Integer.class, isbn);if(stock<0){            //当库存不足时，抛出异常并回滚throw new RuntimeException("库存不足！");}String sql="update stock set stock=stock-1 where Isbn=?";jdbcTemplate.update(sql,isbn);}//实现余额更新@Overridepublic void updateBalance(String username, int price) {String sql2="select balance from account where username=?";Integer balance = jdbcTemplate.queryForObject(sql2, Integer.class, username);if(balance<price){            //当余额不足时，抛出异常并回滚throw new RuntimeException("余额不足！");}String sql="update account set balance=balance-? where username=?";jdbcTemplate.update(sql,price,username);}
}

package com.laola.Impl;import com.laola.dao.Cashier;
import com.laola.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import java.util.List;//事务的传播
//@Transactional
//@Service
public class CashierImpl implements Cashier {//@Autowiredprivate BookService bookService;public void setBookService(BookService bookService) {this.bookService = bookService;}@Overridepublic void checkout(String username, List<String> isbns) {        //遍历购买的书，事务的传播for(String isbn:isbns){bookService.purchase(username,isbn);}}
}

package com.laola.service;public interface BookService {void purchase(String username,String Isbn);
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:context="http://www.springframework.org/schema/context"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:tx="http://www.springframework.org/schema/tx"xmlns:aop="http://www.springframework.org/schema/aop"xsi:schemaLocation="
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsdhttp://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx.xsdhttp://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><context:component-scan base-package="com.laola" /><context:property-placeholder location="db.properties"/>     <!--定义连接池的bean--><bean name ="dataSource" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close"><property name="username" value="${user}" /><property name="password" value="${password}"/><property name="url" value="${url}"/><property name="driverClassName" value="${driver}"/></bean>      <!--定义jdbc模板--><bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"><property name="dataSource" ref="dataSource"/></bean>    <!--定义事务管理器--><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><tx:annotation-driven transaction-manager="transactionManager"/><bean id="bookShopDao"  class="com.laola.Impl.BookShopDaoImpl"><property name="jdbcTemplate" ref="jdbcTemplate"/></bean><bean id="bookService" class="com.laola.Impl.BookServiceImpl"><property name="bookShopDao" ref="bookShopDao"/></bean><bean id="cashier" class="com.laola.Impl.CashierImpl"><property name="bookService" ref="bookService"/></bean>
<!--  配置事务属性--><tx:advice id="txAdvice" transaction-manager="transactionManager"><tx:attributes><tx:method name="*"/></tx:attributes></tx:advice>
<!--    配置事务切点--><aop:config><aop:pointcut id="txpointcut" expression="execution(* com.laola.service.BookService.*(..))"/><aop:advisor advice-ref="txAdvice" pointcut-ref="txpointcut"/></aop:config></beans>

package com.laola.test;import com.laola.dao.BookShopDao;
import com.laola.dao.Cashier;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import java.util.Arrays;public class BookShopTest {public static void main(String[] args) {ApplicationContext ac=new ClassPathXmlApplicationContext("beans.xml");BookShopDao bookShopDao=(BookShopDao) ac.getBean(BookShopDao.class);//int price = bookShopDao.findBookPriceByIsbn("1");Cashier bean = ac.getBean(Cashier.class);        //将用户购买的书放在集合，然后封装到请求参数中bean.checkout("tom", Arrays.asList("1","2"));//System.out.println(price);
    }
}