JavaEE的Spring JDBC与事务管理 实验

package com.lyy; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.transaction.annotation.Transactional; public class BookShopDaoImp implements BookShopDao { private JdbcTemplate jdbcTemplate; public void setJdbcTemplate(JdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; } @Override public int findBookPriceByIsbn(String isbn) { String sql = "select price from book where isbn=?"; return this.jdbcTemplate.queryForObject(sql, Integer.class, isbn); } @Override public void updateBookStock(String isbn, int num) { // 检查书的库存是否足够，若不够，则抛出异常 String sql1 = "select stock from book_stock where isbn=?"; int stock = this.jdbcTemplate.queryForObject(sql1, Integer.class, isbn); if (stock <= num) { throw new RuntimeException("库存不足!"); } String sql = "update book_stock set stock=stock-'" + num + "' where isbn=?"; jdbcTemplate.update(sql, isbn); } @Override public void updateUserAccount(String username, Double price, int num) { // 验证余额是否足够，若不够，则抛出异常 String sql1 = "select balance from account where username=?"; double balance = this.jdbcTemplate.queryForObject(sql1, double.class, username); if (balance < price * num) { throw new RuntimeException("余额不足!"); } String sql = "update account set balance = balance-? where username=?"; jdbcTemplate.update(sql, price * num, username); } @Override @Transactional public void purchase(String username, String isbn, int num) { // 获取书的单价 double price = this.findBookPriceByIsbn(isbn); // 更新书的库存 updateBookStock(isbn, num); /* * 测试事务 ：int i = 1 / 0; * */ // 更新用户余额 updateUserAccount(username, price, num); } }