spring事务实例

spring事务实例

jar包引入

数据库表

有两个用户 张三和 王五 。他们初始账户余额都为 4000。这时候我们进行如下业务：张三向 王五转账 1000 块。那么这在程序中可以分解为两个步骤：

①、张三的账户余额 4000减少 1000 块，剩余 3000块。

②、王五的账户余额 4000增加 1000 块，变为 3000块。

上面两个步骤要么都执行成功，要么都不执行。我们通TransactionTemplate 编程式事务来控制

Dao层

// A code block
public interface AccountDao {
    /**
     * 汇款
     * @param outer 汇款人
     * @param money 汇款金额
     */
    public void out(String outer,int money);
    /**
     * 收款
     * @param inner 收款人
     * @param money 收款金额
     */
    public void in(String inner,int money);
}

DaoImpl层

// An highlighted block
public class AccountDaoImpl extends JdbcDaoSupport implements AccountDao{

	@Override
	public void out(String outer, int money) {
		  this.getJdbcTemplate().update("update user set money = money - ? where username = ?",money,outer);
	}

	@Override
	public void in(String inner, int money) {
		 this.getJdbcTemplate().update("update user set money = money + ? where username = ?",money,inner);		
	}
}

service层

// An highlighted block
public interface AccountService {
	     
	    /**
	     * 转账
	     * @param outer 汇款人
	     * @param inner 收款人
	     * @param money 交易金额
	     */
	    public void transfer(String outer,String inner,int money);
	}

serviceImpl层

// An highlighted block
public class AccountServiceImpl implements AccountService{

	private AccountDao accountDao;
    
    public void setAccountDao(AccountDao accountDao) {
        this.accountDao = accountDao;
    }
    @Override
    public void transfer(String outer, String inner, int money) {
        accountDao.out(outer, money);
    //  int   i=1/0;
        accountDao.in(inner, money);
    }
}

applicationContext.xml

// An highlighted block
<?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/aop
                           http://www.springframework.org/schema/aop/spring-aop.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">
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis"></property>
        <property name="user" value="root"></property>
        <property name="password" value="123456"></property>
    </bean>
     
    <bean id="accountDao" class="com.dao.impl.AccountDaoImpl">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
     
    <bean id="accountService" class="com.service.impl.AccountServiceImpl">
        <property name="accountDao" ref="accountDao"></property>
    </bean>
    
    
    
    
     <!-- 1 事务管理器 -->
    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
     
    <!-- 2 事务详情（事务通知）  ， 在aop筛选基础上，比如对ABC三个确定使用什么样的事务。例如：AC读写、B只读 等
        <tx:attributes> 用于配置事务详情（属性属性）
            <tx:method name=""/> 详情具体配置
                propagation 传播行为 ， REQUIRED：必须；REQUIRES_NEW:必须是新的
                isolation 隔离级别
    -->
    <tx:advice id="txAdvice" transaction-manager="txManager">
        <tx:attributes>
            <tx:method name="transfer" propagation="REQUIRED" isolation="DEFAULT"/>
        </tx:attributes>
    </tx:advice>
     
    <!-- 3 AOP编程，利用切入点表达式从目标类方法中 确定增强的连接器，从而获得切入点 -->
    <aop:config>
        <aop:advisor advice-ref="txAdvice" pointcut="execution(* com.service..*.*(..))"/>
    </aop:config>
</beans>

测试

// An highlighted block
public class Applicatin {
	public static void main(String[] args) {
		 ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
	        AccountService account = (AccountService) context.getBean("accountService");
	        //Tom 向 Marry 转账1000
	        account.transfer("张三", "王五", 1000);
	}
}

结果

发生异常

serviceImpl

// An highlighted block
public class AccountServiceImpl implements AccountService{

	private AccountDao accountDao;
    
    public void setAccountDao(AccountDao accountDao) {
        this.accountDao = accountDao;
    }
    @Override
    public void transfer(String outer, String inner, int money) {
        accountDao.out(outer, money);
         int   i=1/0;    //除0异常
        accountDao.in(inner, money);
    }
}

结果

除0异常

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