Spring学习（十三）-事务准备

1.BookShopDao.java接口类

package com.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：使对应库存-1
public void updateBookStock(String isbn);
//更新用户账户余额：使username的balance-price
public void updateUserAccount(String isbn,int price);
}

2.BookShopImpl.java实现类

package com.spring.tx;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository("bookShopDao")
public class BookShopImpl 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);

}

}

3.BookShopService.java用户买书的接口

package com.spring.tx;

public interface BookShopService {

public void purchase(String username,String isbn);

}

4.BookShopServiceImpl.java实现类

package com.spring.tx;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service("bookShopService")
public class BookShopServiceImpl implements BookShopService {

@Autowired
public BookShopDao bookShopDao;
@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);

}

}

5.异常处理类包括余额不足与库存不足

package com.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) {
super(message);
// TODO Auto-generated constructor stub
}

}

package com.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) {
super(message);
// TODO Auto-generated constructor stub
}
4000

}

6.Test实现类

package com.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("springXML/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"));
}

}

7.ApplicationContext.xml

<?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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> 
<context:component-scan base-package="com.spring"></context:component-scan>

<!-- 导入资源文件 -->
<context:property-placeholder location="classpath:db.properties"/>
<!-- 配置C3p0数据源 -->
<bean id="dataSource"
class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="${jdbc.driverClass}"/>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"/>
<property name="user" value="${jdbc.user}"/>
<property name="password" value="${jdbc.password}"/>
<property name="initialPoolSize" value="${jdbc.initialPoolSize}"/>
<property name="minPoolSize" value="${jdbc.minPoolSize}"/>
<property name="maxPoolSize" value="${jdbc.maxPoolSize}"/>
</bean>
<!-- 配置Spring中JdbcTemplate(Jdbc模板类) -->
<bean id="jdbcTemplate"
class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>

<!-- 配置NameParameterJdbcTemplate该对象可以使用具名参数，其没有无参构造器，必须为其指定参数 -->
<bean id="nameParameterJdbcTemplate"
class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
<constructor-arg ref="dataSource"></constructor-arg>
</bean>
</beans>