xml 方式声明式事务案例

xml 方式声明式事务案例

1. 创建数据库表

表名 tbl_account

create table tbl_account(
	id int AUTO_INCREMENT PRIMARY KEY,
    name varchar(10) NOT NULL,
    money double NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

框架结构

2. jdbc.properties 文件，配置 JDBC 连接

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/table_account
jdbc.username=root
jdbc.password=123456

3. xml文件配置

<?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:aop="http://www.springframework.org/schema/aop"
       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.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd
">
    <!--    组件扫描-->
    <context:component-scan base-package="com.itheima"></context:component-scan>
    <!--    加载properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>
    <!--    配置数据源信息-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <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SqlSessionFactoryBean,作用将SqlSessionFactory存储到Spring容器-->
    <bean class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!-- MapperScannerConfigurer，作用扫描指定包，产生Mapper对象存储到Spring容器-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.itheima.mapper"></property>
    </bean>

    <!--配置平台事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!--配置Spring提供好的通知advice-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <!--            
            配置不同的方法的事务属性
            name: 方法名称 * 代表通配符 添加操作addUser、addAccount、addOrder 可以采用 add*
            isolation: 事务的隔离级别，解决事务并发问题
            timeout: 超时时间 默认-1 单位 秒
            read-only: 是否只读, 查询操作设置为只读
            propagation: 事务的传播行为，解决事务嵌套问题
            -->
            <tx:method name="*"/>
        </tx:attributes>
    </tx:advice>

    <!--事务增强的AOP-->
    <aop:config>
        <!-- 配置切入点表达式-->
        <aop:pointcut id="txPointcut" expression="execution(* com.itheima.service.impl.*.*(..))"/>
        <!-- 配置织入关系 通知advice-ref 引入Spring提供好的-->
        <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointcut"/>

    </aop:config>
</beans>

4. AccountMapper 接口

public interface AccountMapper {

    @Update("update tbl_account set money = money - #{money} where name = #{name}")
    public void incrMoney(@Param("name") String name, @Param("money") Double money);

    @Update("update tbl_account set money = money + #{money} where name = #{name}")
    public void decrMoney(@Param("name") String name, @Param("money") Double money);

}

5. AccountService 接口

public interface AccountService {
    void transfer(String outName, String inName, Double money);
}

6. AccountService 的实现类 AccountServiceImpl

@Service("accountService")
public class AccountServiceImpl implements AccountService {
    
    @Autowired
    private AccountMapper accountMapper;

    @Override
    public void transfer(String outName, String inName, Double money) {
        accountMapper.decrMoney(outName, money);
        accountMapper.incrMoney(inName, money);
    }
}

7. 测试操作数据库 转账操作

public class AccountTest {

    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");

        AccountService accountService = applicationContext.getBean(AccountService.class);
        
        accountService.transfer("Tom", "Jerry", 500.0);
    }
}

正常情况下，Tom给 Jerry 转账成功

若给业务层加异常，在有事务的情况下，事务会回滚，否则不回滚(存在 Tom 只减钱，Jerry 不加钱)；

@Service("accountService")
public class AccountServiceImpl implements AccountService {
    
    @Autowired
    private AccountMapper accountMapper;

    @Override
    public void transfer(String outName, String inName, Double money) {
        accountMapper.decrMoney(outName, money);
        int i = 1 / 0;
        accountMapper.incrMoney(inName, money);
    }
}