用户购买图书，购买成功，库存更新，账户余额更新，若余额或者库存不够，均不能购买成功，产生异常
account: 账户表(包括用户名和余额)
book：图书表(id, 书名, 图书价格)
book_stock：库存表(id, 图书库存)
1. 图书购买时的接口
package com.atguigu.spring.tx;
public interface BookShopDao {
//根据书号获取书的单价
public int findBookPriceByIsbn(String isbn);
//更新书的库存, 使书号对应的库存 - 1
public void updateBookStock(String isbn);
//更新用户的账户余额: 使 username 的 balance - price
public void updateUserAccount(String username, int price);
}
package com.atguigu.spring.tx;
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 {
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public int findBookPriceByIsbn(String isbn) {
String sql = "select price from book where isbn = ?";
return jdbcTemplate.queryForObject(sql, Integer.class, isbn);
}
@Override
public void updateBookStock(String isbn) {
//检查书的库存是否足够, 若不够, 则抛出异常
String sql2 = "select stock from book_stock where isbn = ?";
int stock = jdbcTemplate.queryForObject(sql2, Integer.class, isbn);
if (stock == 0) {
throw new BookStockException("库存不足！");
}
String sql = "update book_stock set stock = stock -1 where isbn = ?";
jdbcTemplate.update(sql, isbn);
}
@Override
public void updateUserAccount(String username, int price) {
//验证余额是否足够, 若不足, 则抛出异常
String sql2 = "select balance from account where username = ?";
int balance = jdbcTemplate.queryForObject(sql2, Integer.class, username);
if(balance < price){
throw new UserAccountException("余额不足!");
}
String sql = "update account set balance = balance - ? where username = ?";
jdbcTemplate.update(sql, price, username);
}
}
package com.atguigu.spring.tx;
public interface BookShopService {
public void purchase(String username, String isbn);
}
package com.atguigu.spring.tx;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("bookShopService")
public class BookShopServiceImpl implements BookShopService {
@Autowired
private BookShopDao bookShopDao;
//添加事务注解
@Transactional
@Override
public void purchase(String username, String isbn) {
//1. 获取书的单价
int price = bookShopDao.findBookPriceByIsbn(isbn);
//2. 更新书的库存
bookShopDao.updateBookStock(isbn);
//3. 更新用户余额
bookShopDao.updateUserAccount(username, price);
}
}
2. 测试方法
package com.atguigu.spring.tx;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SpringTransactionTest {
private ApplicationContext ctx = null;
private BookShopDao bookShopDao = null;
private BookShopService bookShopService = null;
{
ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
bookShopDao = ctx.getBean(BookShopDao.class);
bookShopService = ctx.getBean(BookShopService.class);
}
@Test
public void testBookShopService() {
bookShopService.purchase("AA", "1001");
}
@Test
public void testBookShopDaoUpdateUserAccount(){
bookShopDao.updateUserAccount("AA", 100);
}
@Test
public void testBookShopDaoUpdateBookStock(){
bookShopDao.updateBookStock("1001");
}
@Test
public void testBookShopDaoFindPriceByIsbn() {
System.out.println(bookShopDao.findBookPriceByIsbn("1001"));
}
}
3. 错误则抛出异常
package com.atguigu.spring.tx;
public class BookStockException extends RuntimeException{
/**
*
*/
private static final long serialVersionUID = 1L;
public BookStockException() {
super();
// TODO Auto-generated constructor stub
}
public BookStockException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
// TODO Auto-generated constructor stub
}
public BookStockException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}
public BookStockException(String message) {
super(message);
// TODO Auto-generated constructor stub
}
public BookStockException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}
}
package com.atguigu.spring.tx;
public class UserAccountException extends RuntimeException{
/**
*
*/
private static final long serialVersionUID = 1L;
public UserAccountException() {
super();
// TODO Auto-generated constructor stub
}
public UserAccountException(String message, Throwable cause, boolean enableSuppression,
boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
// TODO Auto-generated constructor stub
}
public UserAccountException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}
public UserAccountException(String message) {
super(message);
// TODO Auto-generated constructor stub
}
public UserAccountException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}
}
<?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: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.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
<context:component-scan base-package="com.atguigu.spring"></context:component-scan>
<!-- 导入资源文件 -->
<context:property-placeholder location="classpath:db.properties"/>
<!-- 配置 C3P0 数据库 -->
<bean id="dataSource"
class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="user" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="driverClass" value="${jdbc.driverClass}"></property>
<property name="initialPoolSize" value="${jdbc.initPoolSize}"></property>
<property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
</bean>
<!-- 配置 Spring 的 JdbcTemplate -->
<bean id="jdbcTemplate"
class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置事务管理器 -->
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 启用事务 -->
<tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
原文：http://blog.51cto.com/13416247/2088698