ext:property-placeholder location="jdbc.properties"></context:property-placeholder>
<!-- 配置数据源 -->
<bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
<!--通过${key}的方式访问外部属性文件的value-->
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!-- 配置 JdbcTemplate -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<!-- 装配数据源 -->
<property name="dataSource" ref="datasource"></property>
</bean>
</beans>
15.1.4、创建持久层接口BookDao及其实现类
package org.rain.spring.dao;
/**
* @author liaojy
* @date 2023/9/3 - 17:34
*/
public interface BookDao {
/**
* 查询图书的价格
* @param bookId
* @return
*/
Integer getPriceByBookId(Integer bookId);
/**
* 更新图书的库存
* @param bookId
*/
void updateStockOfBook(Integer bookId);
/**
* 更新用户的余额
* @param userId
* @param price
*/
void updateBalanceOfUser(Integer userId,Integer price);
}
package org.rain.spring.dao.impl;
import org.rain.spring.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;
/**
* @author liaojy
* @date 2023/9/3 - 17:36
*/
@Repository
public class BookDaoImpl implements BookDao {
@Autowired
private JdbcTemplate jdbcTemplate;
public Integer getPriceByBookId(Integer bookId) {
String sql = "select price from t_book where book_id = ?";
Integer price = jdbcTemplate.queryForObject(sql, Integer.class,bookId);
return price;
}
public void updateStockOfBook(Integer bookId) {
String sql = "update t_book set stock = stock -1 where book_id = ?";
jdbcTemplate.update(sql, bookId);
}
public void updateBalanceOfUser(Integer userId, Integer price) {
String sql = "update t_user set balance = balance - ? where user_id = ?";
jdbcTemplate.update(sql,price,userId);
}
}
15.1.5、创建业务层接口BookService及其实现类
package org.rain.spring.service;
/**
* @author liaojy
* @date 2023/9/3 - 17:52
*/
public interface BookService {
void buyBook(Integer bookId,Integer userId);
}
package org.rain.spring.service.impl;
import org.rain.spring.dao.BookDao;
import org.rain.spring.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* @author liaojy
* @date 2023/9/3 - 17:53
*/
@Service
public class BookServiceImpl implements BookService {
@Autowired
private BookDao bookDao;
public void buyBook(Integer bookId, Integer userId) {
//查询图书的价格
Integer price = bookDao.getPriceByBookId(bookId);
//更新图书的库存
bookDao.updateStockOfBook(bookId);
//更新用户的余额
bookDao.updateBalanceOfUser(userId,price);
}
}
15.1.6、创建控制层BookController
注意：因为控制层没用到接口，所以方法的访问修饰符要手动设置
package org.rain.spring.