Spring中提供了七种事务的传播行为：
PROPAGATION_REQUIRED：默认值，最常用，统一事务，出现异常，全部回滚
其余参考Spring事务处理word文档。
0、原转账业务（不含事务处理）
MyAspect：
@Component
public class MyAspect {
@Autowired
UserMapper userMapper;
@Autowired
AccountMapper accountMapper;
/**
* 判断是否能转账
* @param point 切入点
* @return 1 可以转账
*/
public int transAccount(ProceedingJoinPoint point){
//拿到切入点参数
Object[] args = point.getArgs();
//转出人id
int outId = (int)args[0];
//转账金额
double money = (double)args[2];
//转出人cid
int cidOut = userMapper.getCidById(outId);
//获取转出人账户余额
double balance = accountMapper.getMoney(cidOut);
//判断转出的账户余额与转出金额比较
//转出>余额 异常：余额不足
if (money>balance){
throw new RuntimeException("余额不足，转账失败");
}else {
//执行转账
try {
int i = (int)point.proceed();
return i;
} catch (Throwable throwable) {
throwable.printStackTrace();
}
}
return 0;
}
}
通过aop编程，给原转账业务增加上面的增强类方法（基于xml）：
<?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: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/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<aop:config>
<aop:pointcut id="p1" expression="execution(* com.yd.service.impl.AccountServiceImpl.transferAccountIn(..))"/>
<aop:aspect ref="myAspect">
<aop:around method="transAccount" pointcut-ref="p1"></aop:around>
</aop:aspect>
</aop:config>
<!-- 强制使用cglib代理-->
<aop:aspectj-autoproxy proxy-target-class="true"></aop:aspectj-autoproxy>
</beans>
一、基于xml的事务
通过AOP编程，给转账业务添加事务处理功能
- 在转账是可能出现时间延时或其他异常，导致事务不统一
- 以下用aop方式，给转账业务添加事务
- 在不用更改源代码的情况下添加事务处理
transaction.xml:
<?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: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/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"> <!-- bean definitions here -->
<!-- 配置事物管理器的切面 -->
<bean id="transactionMananger" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- 配置事物传播行为 ：其实就是哪些方法应该受什么样的事物控制-->
<tx:advice id="advice" transaction-manager="transactionMananger">
<tx:attributes>
<tx:method name="transferAccountIn" propagation="REQUIRED"/>
</tx:attributes>
</tx:advice>
<!-- 哪些类下的方法需要参与到当前的事物管理中,配置切入点 -->
<aop:config>
<aop:advisor advice-ref="advice" pointcut="execution(* com.yd.service.impl.AccountServiceImpl.*(..))"/>
</aop:config>
</beans>
切入点-AccountServiceImpl:
@Service
public class AccountServiceImpl implements AccountService {
@Autowired
AccountMapper accountMapper;
@Autowired
UserMapper userMapper;
@Override
public int transferAccountIn(int idOut, int idIn, double money) {
//转入人cid
int cidIn = userMapper.getCidById(idIn);
//转入金额
int in = accountMapper.updateIn(cidIn,money);
//模拟异常
System.out.println(1/0);
//转出人cid
int cidOut = userMapper.getCidById(idOut);
//转出金额
int out = accountMapper.updateOut(cidOut,money);
return in + out;
}
}
- 将事务添加在transferAccountIn()方法上，只要有异常，其中的事务全部回滚
运行代码：
public class Demo {
public static void main(String[] args) {
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("mybatis.xml", "spring.xml","aspect.xml","tansaction.xml");
AccountServiceImpl accountServiceImpl = (AccountServiceImpl)ac.getBean("accountServiceImpl");
int res = accountServiceImpl.transferAccountIn(2,1,900);
if (res==2){
System.out.println("转账成功！");
}else {
System.out.println("转账失败！");
}
}
}
运行结果：
- 出现异常，事务回滚
二、基于注解的事务
1. 在transacion.xml配置文件中添加：开启注解事务
<?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: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/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"> <!-- bean definitions here -->
<!-- 配置事物管理器的切面（必须要） -->
<bean id="transactionMananger" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<aop:aspectj-autoproxy proxy-target-class="true"/> <!--强制使用Cglib代理-->
<!-- 开启注解事务-->
<tx:annotation-driven transaction-manager="transactionMananger"></tx:annotation-driven>
</beans>
2.在相应的方法上添加注解
@Transactional(propagation = Propagation.REQUIRED)
- 在类上加此注解，表示当前类下所有方法都参与指定的事务管理
- 在方法上加此注解，表示该方法执行指定的事务管理
@Service
public class AccountServiceImpl implements AccountService {
@Autowired
AccountMapper accountMapper;
@Autowired
UserMapper userMapper;
@Override
@Transactional(propagation = Propagation.REQUIRED)
public int transferAccountIn(int idOut, int idIn, double money) {
//转入人cid
int cidIn = userMapper.getCidById(idIn);
//转入金额
int in = accountMapper.updateIn(cidIn,money);
System.out.println(1/0);
//转出人cid
int cidOut = userMapper.getCidById(idOut);
//转出金额
int out = accountMapper.updateOut(cidOut,money);
return in + out;
}
}
运行代码（与前面一致）：
public class Demo {
public static void main(String[] args) {
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("mybatis.xml", "spring.xml","aspect.xml","tansaction.xml");
AccountServiceImpl accountServiceImpl = (AccountServiceImpl)ac.getBean("accountServiceImpl");
int res = accountServiceImpl.transferAccountIn(2,1,900);
if (res==2){
System.out.println("转账成功！");
}else {
System.out.println("转账失败！");
}
}
}
运行结果：
同样会出现异常，回滚
- 注解开发更方便
- 需要修改源码，在源码上加注解
