Spring注解事务大致的实现原理

1. 自定义注解  @MyTransaction

/**
 * @author yangxj
 * @see org.springframework.transaction.annotation.SpringTransactionAnnotationParser
 * @see org.springframework.transaction.interceptor.TransactionAttribute
 * @see org.springframework.transaction.TransactionDefinition
 */
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyTransaction {
    String value() default "";
}

2. 自定义通知Advice

/**
 * @author yangxj
 * 
 * @see org.springframework.transaction.PlatformTransactionManager
 * @see org.springframework.jdbc.datasource.DataSourceTransactionManager
 * @see org.springframework.transaction.interceptor.TransactionInterceptor
 */
@Slf4j
public class MyTransactionInterceptor implements MethodInterceptor {

    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
        log.info("拦截到事务方法：{}", methodInvocation.getMethod().getName());
        try {
             return methodInvocation.proceed();
            // commit   提交事务    
        } catch (Exception e) {
            // rollback 回滚事务
        }
        return null;
    }
}

3. 织入

/**
 * @author yangxj

* @see org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration
* @see org.springframework.transaction.interceptor.BeanFactoryTransactionAttributeSourceAdvisor

 */
@Configuration
public class CommonConfiguration {
    @Bean
    public DefaultPointcutAdvisor myTransactionPointcutAdvisor() {
        DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(); // 切面  Aspect
        advisor.setPointcut(new AnnotationMatchingPointcut(null, MyTransaction.class));  // 方法级别注解匹配 切入点 pointcut
        advisor.setAdvice(new MyTransactionInterceptor());  // 通知 advice
        return advisor;
    }
}

4. 演示

 

 原理： 对应加了@Transactional 的方法，spring会为其生成一个代理bean,当调用方法时，使用事务管理器（TransactionManager）开启一个数据库连接并关闭autocommit,这样当方法异常时回滚否则提交事务