Java分布式事务实现原理与解决方案详解

// 简化的2PC协调者实现
public class TwoPhaseCommitCoordinator {
    public boolean executeTransaction(List<Participant> participants) {
        // 阶段一：准备阶段
        boolean allPrepared = participants.stream()
            .allMatch(Participant::prepare);
        // 阶段二：提交或回滚
        if(allPrepared) {
            participants.forEach(Participant::commit);
            return true;
        } else {
            participants.forEach(Participant::rollback);
            return false;
        }
    }
}
interface Participant {
    boolean prepare();  // 准备资源
    void commit();     // 提交事务
    void rollback();   // 回滚事务
}

@LocalTCC
public interface AccountService {
    @TwoPhaseBusinessAction(name = "deduct", commitMethod = "confirm", rollbackMethod = "cancel")
    boolean deduct(BusinessActionContext actionContext, 
                  @BusinessActionContextParameter(paramName = "userId") String userId,
                  @BusinessActionContextParameter(paramName = "amount") BigDecimal amount);
    boolean confirm(BusinessActionContext actionContext);
    boolean cancel(BusinessActionContext actionContext);
}

{
  "Name": "orderProcess",
  "States": {
    "reduceInventory": {
      "Type": "ServiceTask",
      "ServiceName": "inventoryService",
      "ServiceMethod": "deduct",
      "CompensateState": "compensateReduceInventory",
      "Next": "createOrder"
    },
    "createOrder": {
      "Type": "ServiceTask",
      "ServiceName": "orderService",
      "ServiceMethod": "create",
      "CompensateState": "compensateCreateOrder"
    }
  }
}

TransactionMQProducer producer = new TransactionMQProducer("group");
producer.setTransactionListener(new TransactionListener() {
    @Override
    public LocalTransactionState executeLocalTransaction(Message msg, Object arg) {
        // 执行本地事务
        return orderService.createOrder(msg) ? 
            LocalTransactionState.COMMIT_MESSAGE : 
            LocalTransactionState.ROLLBACK_MESSAGE;
    }
    @Override
    public LocalTransactionState checkLocalTransaction(MessageExt msg) {
        // 检查本地事务状态
        return orderService.checkOrderStatus(msg) ? 
            LocalTransactionState.COMMIT_MESSAGE : 
            LocalTransactionState.ROLLBACK_MESSAGE;
    }
});

seata:
  enabled: true
  application-id: order-service
  tx-service-group: my-tx-group
  service:
    vgroup-mapping:
      my-tx-group: default
    grouplist:
      default: 127.0.0.1:8091
  config:
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848
  registry:
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848

<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-spring-boot-starter</artifactId>
    <version>1.6.1</version>
</dependency>

@RestController
public class OrderController {
    @GlobalTransactional
    @PostMapping("/order")
    public String createOrder(@RequestBody OrderDTO orderDTO) {
        // 扣减库存
        inventoryFeignClient.deduct(orderDTO.getProductId(), orderDTO.getCount());
        // 创建订单
        orderService.create(orderDTO);
        return "success";
    }
}