声明式事务

Connection connection = JdbcUtils.getConnection();//得到连接
try {
    //1. 先设置事务不要自动提交，默认true
    connection.setAutoCommint(false);
    //2. 进行各种crud
    //多个表的修改，添加，删除
    //3. 提交
    connection.commit();
} catch (Exception e) {
    //4. 回滚
    conection.rollback();
}

@Repository
public class GoodsDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;
    public Float queryPriceById(Integer id) {
        String sql = "SELECT price From goods Where goods_id=?";
        //获取商品价格
        Float price = jdbcTemplate.queryForObject(sql, Float.class, id);
        return price;
    }
    public void updateBalance(Integer user_id, Float money) {
        String sql = "UPDATE user_account SET money=money-? Where user_id=?";
        //修改用户余额
        jdbcTemplate.update(sql, money, user_id);
    }
    public void updateAmount(Integer goods_id, int amount){
        String sql = "UPDATE goods_amount SET goods_num=goods_num-? Where  goods_id=?";
        //修改商品库存
        jdbcTemplate.update(sql, amount , goods_id);
    }
}

<?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"
xmlns:aop="http://www.springframework.org/schema/aop"
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.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 引入外部属性文件-->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    <!-- 配置数据源-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="${jdbc.userName}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="driverClass" value="${jdbc.driverClass}"></property>
        <property name="jdbcUrl" value="${jdbc.url}"></property>
    </bean>
    <!-- 配置JdbcTemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!-- 将上面的数据源分配给jdbcTemplate -->
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 配置事务管理器-->
    <bean id="dataSourceTransactionManager"
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
      <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 开启基于注解的声明式事务功能-->
    <tx:annotation-driven transaction-manager="dataSourceTransactionManager"/>
    <!-- 加入自动扫描包dao -->
    <context:component-scan base-package="com.nlc.spring.tx.dao"/>
</beans>

public class TxTest {
    /**
    * 查询商品的价格
    */
    @Test
    public void queryPriceByIdTest() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("tx_ioc.xml");
        System.out.println("查询价格");
        GoodsDao bean = ioc.getBean(GoodsDao.class);
        Float price = bean.queryPriceById(1);
        System.out.println(" 1 号商品的价格= " + price);
    }
    /**
    * 修改用户余额(购买商品后)
    */
    @Test
    public void updateBalanceTest() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("tx_ioc.xml");
        GoodsDao bean = ioc.getBean(GoodsDao.class);
        bean.updateBalance(1, 30.5f);
        System.out.println("====修改余额成功====");
    }
    /**
    * 测试修改商品的库存量
    */
    @Test
        public void updateAmountTest() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("tx_ioc.xml");
        GoodsDao bean = ioc.getBean(GoodsDao.class);
        韩顺平Java 工程师
        bean.updateAmount(1, 2);
        System.out.println("====修改商品库存量成功====");
    }
}

@Service
public class GoodsService {
    @Autowired
    private GoodsDao goodsDao;
    /**
    * 购买商品[没有使用事务]
    * @param user_id
    * @param goods_id
    * @param num
    */
    public void buyGoods(int user_id, int goods_id, int num) {
    //查询到商品价格
    Float goods_price = goodsDao.queryPriceById(goods_id);
    //购买商品，减去余额
    goodsDao.updateBalance(user_id, goods_price * num);
    // 可以自己模拟一个异常便于查看效果, 会发生数据库数据不一致现象
    // int i = 10 / 0;
    //更新库存
    goodsDao.updateAmount(goods_id, num);
    }
}

<!-- 加入自动扫描包service -->
<context:component-scan base-package="com.nlc.spring.tx.service"/>

//测试购买商品
  @Test
  public void buyGoodsTest() {
      ApplicationContext ioc = new ClassPathXmlApplicationContext("tx_ioc.xml");
      GoodsService bean = ioc.getBean(GoodsService.class);
      bean.buyGoods(1, 2, 1);
      System.out.println("====购买商品成功====");
  }

/**
* 购买商品(使用spring 的声明式事务)
* 默认事务是传播属性:REQUIRED
*/
@Transactional
public void buyGoodsByTx(int user_id, int goods_id, int num) {
    //查询到商品价格
    Float goods_price = goodsDao.queryPriceById(goods_id);
    //购买商品，减去余额
    goodsDao.updateBalance(user_id, goods_price * num);
   // 可以自己模拟一个异常便于查看效果, 会发生数据库数据不一致现象
    // int i = 10 / 0;
    //更新库存
    goodsDao.updateAmount(goods_id, num);
}

// 测试购买商品(使用了声明式事务)
@Test
public void buyGoodsByTxTest() {
    ApplicationContext ioc = new ClassPathXmlApplicationContext("tx_ioc.xml");
    GoodsService bean = ioc.getBean(GoodsService.class);
    //使用buyGoodsByTx()
    bean.buyGoodsByTx(1, 2, 1);
    System.out.println("====购买商品成功====");
}