Spring编程式事务（本地事务）

使用 TransactionTemplate等类和 API 手动管理事务，控制事务的新建、提交、回滚等过程

方式一：使用 TransactionTemplate（推荐方式）

@Service
public class OrderService {
    private final TransactionTemplate transactionTemplate;
    private final OrderRepository orderRepository;
    private final InventoryRepository inventoryRepository;

    public OrderService(PlatformTransactionManager txManager,
                       OrderRepository orderRepository,
                       InventoryRepository inventoryRepository) {
        this.transactionTemplate = new TransactionTemplate(txManager);
        this.orderRepository = orderRepository;
        this.inventoryRepository = inventoryRepository;
    }

    public void createOrder(Order order) {
        transactionTemplate.execute(status -> {
            try {
                // 操作1: 保存订单
                orderRepository.save(order);
                
                // 操作2: 扣减库存
                inventoryRepository.deductStock(order.getProductId(), order.getQuantity());
                
                return "SUCCESS";
            } catch (Exception e) {
                status.setRollbackOnly(); // 标记回滚
                throw new RuntimeException("Transaction rolled back", e);
            }
        });
    }
}

方式二：使用 PlatformTransactionManager（精细控制）

@Service
public class PaymentService {
    private final PlatformTransactionManager txManager;
    private final PaymentRepository paymentRepository;

    public PaymentService(PlatformTransactionManager txManager, PaymentRepository paymentRepository) {
        this.txManager = txManager;
        this.paymentRepository = paymentRepository;
    }

    public void processPayment(Payment payment) {
        // 定义事务属性（传播行为、隔离级别）
        DefaultTransactionDefinition definition = new DefaultTransactionDefinition();
        definition.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
        definition.setIsolationLevel(TransactionDefinition.ISOLATION_READ_COMMITTED);
        
        TransactionStatus status = txManager.getTransaction(definition);
        
        try {
            // 业务操作
            paymentRepository.save(payment);
            
            // 模拟外部服务调用（若失败需回滚）
            if (!externalPaymentGateway.charge(payment)) {
                throw new RuntimeException("Payment failed");
            }
            
            txManager.commit(status);
        } catch (Exception e) {
            txManager.rollback(status);
            throw e;
        }
    }
}

为什么不建议用声明式事务？

1）粒度不可控，最低是方法级别，容易造成大事务

2）使用不当，可能造成事务回滚不完全造成业务故障，如方法中调用了第三方接口，接口调用不能回滚

3）失效场景众多，一不小心就会造成事务失效