1. 准备工作
1> 添加接口 BookShopDao
package com.tx;
public interface BookShopDao {
//根据书号获取书的单价
public int findBookPriceByIsbn(int isbn);
//更新书的库存， 使书号对应的书的库存 -1
public void updateBookStock(int isbn);
//更新用户账户余额： 使 username 的 balance - price
public void updateUserAccount(String username, int price);
}2> 添加接口 BookShopDao 的实现类 BookShopDaoImpl
package com.tx; import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository; @Repository("bookShopDao")
public class BookShopDaoImpl implements BookShopDao{ @Autowired
private JdbcTemplate jdbcTemplate; @Override
public int findBookPriceByIsbn(int isbn) {
String sql = "select price from book where isbn = ?"; return jdbcTemplate.queryForObject(sql, Integer.class, isbn);
} @Override
public void updateBookStock(int isbn) {
String sql2 = "select stock from book_stock where isbn = ?";
Integer num = jdbcTemplate.queryForObject(sql2, Integer.class, isbn);
if(num == 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) {
String sql2 = "select balance from account where username = ?";
Integer balance = jdbcTemplate.queryForObject(sql2, Integer.class, username);
if(balance < price) {
throw new BookAccountException("余额不足");
} String sql = "update account set balance = balance-? where username = ?";
jdbcTemplate.update(sql, price, username);
} }
3> 添加 spring 配置文件
<?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:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd
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/aop http://www.springframework.org/schema/aop/spring-aop-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.tx"></context:component-scan>
<context:property-placeholder location="classpath:db.properties"/>
<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="driverClass" value="${jdbc.driverClass}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="initialPoolSize" value="${jdbc.initialPoolSize}"></property>
<property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
</bean> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean> <!-- 配置事物管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean> <!-- 启用事物注解 -->
<tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
4> 添加测试类 SpringTest
package com.tx; import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class SpringTest { private ApplicationContext ctx;
private BookShopDao bookShopDao;
private BookShopService bookShopService; {
ctx = new ClassPathXmlApplicationContext("bean-jdbc.xml");
bookShopDao = ctx.getBean(BookShopDaoImpl.class);
bookShopService = ctx.getBean(BookShopService.class);
} /**
* 测试 根据书号获取书的单价
*/
@Test
public void testFind() {
int price = bookShopDao.findBookPriceByIsbn(1002);
System.out.println(price);
} /**
* 测试 更新书的库存， 使书号对应的书的库存 -1
*/
@Test
public void testUpdateStock() {
bookShopDao.updateBookStock(1001);
} /**
* 测试 更新用户账户余额： 使 username 的 balance - price
*/
@Test
public void testUpdateAccount() {
bookShopDao.updateUserAccount("AA", 20);
} /**
* 测试 事物
*/
@Test
public void testPurchase() {
bookShopService.purchase("AA", 1001);
} }
5> 添加 BookShopService 接口
package com.tx;
public interface BookShopService {
public void purchase(String username, int isbn);
}6> 添加 BookShopServiceImpl 实现类
package com.tx; import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional; @Service
public class BookShopServiceImpl implements BookShopService { @Autowired
private BookShopDao bookShopDao; @Transactional //添加事物注解
@Override
public void purchase(String username, int isbn) {
//1. 获取书的单价
int price = bookShopDao.findBookPriceByIsbn(isbn); //2. 更新库存
bookShopDao.updateBookStock(isbn); //3. 更新账户余额
bookShopDao.updateUserAccount(username, price);
} }
7> 添加 BookAccountException 和 BookStockException 异常类
package com.tx;
public class BookAccountException extends RuntimeException{
/**
*
*/
private static final long serialVersionUID = 1L;
public BookAccountException() {
super();
// TODO Auto-generated constructor stub
}
public BookAccountException(String message, Throwable cause, boolean enableSuppression,
boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
// TODO Auto-generated constructor stub
}
public BookAccountException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}
public BookAccountException(String message) {
super(message);
// TODO Auto-generated constructor stub
}
public BookAccountException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}
}package com.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
}
}2. 配置事物管理器
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
3. 启用事物注解
<tx:annotation-driven transaction-manager="transactionManager"/>
4. 添加事物注解 （在需要进行事物处理的地方加入事物注解）
@Transactional //添加事物注解
@Override
public void purchase(String username, int isbn) {
5. 事物注解详解
/**
* 添加事物注解
* 1. 使用 propagation 指定事物的传播行为，（由内而外传播） 即当前的事物方法被另外一个事物方法调用时
* 如何使用事物， 默认取值为 REQUIRED， 即使用调用方法的事物(也就是说， 买2本书， 要么全部成功购买， 要么事物回滚)
* REQUIRES_NEW : 表示新开启一个事物，调用的事物方法的事物被挂起 （意思是， 如果够买一本的钱，就买一本， 其他回滚）
*
* 2. 使用 isolation 指定事物的隔离级别， 最常用的取值为 READ_COMMITTED(读已提交)
*
* 3. 默认情况下 Spring 的声明式事物对所有的运行时异常进行回滚， 也可以通过对应的属性进行设置
* noRollbackFor: 对指定异常不进行回滚 ， 也就不是一个事物了， 也可由其他回滚设置， 通常情况取默认值
*
* 4. 使用 readOnly 指定事物是否只读， 不更新数据， 若真的是一个只读取数据库的方法， 应设置为 ： readOnly = true
*
* 5. 使用 timeout 指定强制回滚之前事物可以占用的时间， 也就是在指定时间还没执行完成就回直接进行回滚，单位为秒
*/
@Transactional(propagation=Propagation.REQUIRES_NEW, isolation=Isolation.READ_COMMITTED,
noRollbackFor= {BalanceException.class}, readOnly = false, timeout=1)
@Override
public void buyBook(String username, int isbn) {