Spring学习-day13

需求：

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

数据表:

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)

代码实现:

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>