基于切面实现自定义事务

一、介绍
二、步骤
三、效果
四、源码

一、介绍

仿造spring中的@Transactional注解实现简易版的事务。通过spring中的aop拦截所有带自定义事务注解的方法去实现事务的控制。

二、步骤

创建一个自定义事务注解CustomTransactional.java

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface CustomTransactional {
}

事务注解切面拦截类CustomTransactionalInterceptor.java

@Aspect
@Component
public class CustomTransactionalInterceptor {

    @Autowired
    private PlatformTransactionManager platformTransactionManager;

    @Autowired
    private TransactionDefinition transactionDefinition;

    // 匹配所有方法上加上@CustomTransactional注解的方法
    @Pointcut(value = "@annotation(com.linmt.transaction.annocations.CustomTransactional)")
    public void transactionalPointCut() {
    }

    @Before(value = "transactionalPointCut()")
    // 开启事务
    public void beforeTransactionalHandle() {
        TransactionStatus transactionStatus = platformTransactionManager.getTransaction(transactionDefinition);
        TransactionStatusContext.setTransactionStatus(transactionStatus);
    }

    @AfterReturning(value = "transactionalPointCut()")
    // 方法正常返回
    public void afterReturningTransactionalHandle() {
        TransactionStatus transactionStatus = TransactionStatusContext.getTransactionStatus();
        platformTransactionManager.commit(transactionStatus);
    }

    @AfterThrowing(value = "transactionalPointCut()", throwing = "e")
    // 方法执行抛出异常
    public void afterThrowingTransactionalHandle(Throwable e) {
        TransactionStatus transactionStatus = TransactionStatusContext.getTransactionStatus();
        platformTransactionManager.rollback(transactionStatus);

        // 此处可以根据异常类型进行判断是否回滚
    }
}

创建一个TransactionStatus上下文类

 public class TransactionStatusContext {
     private static ThreadLocal<TransactionStatus> threadLocal = new ThreadLocal<>();

     public static void setTransactionStatus(TransactionStatus transactionStatus) {
         threadLocal.set(transactionStatus);
     }

     public static TransactionStatus getTransactionStatus() {
         return threadLocal.get();
     }

     public static void clearTransactionStatus() {
         threadLocal.remove();
     }
 }

新建一个service类

@Service
public class UserServiceImpl implements IUserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    @CustomTransactional
    public void insertOne(UserPo userPo) {
        userMapper.insertOne(userPo);

        int i = 1/0;
    }
}