2.两阶段提交，我们以账户服务为例，接口定义如下：
@FeignClient(value = "account-server") @LocalTCC public interface AccountApi { /** * 扣减账户余额 * @param actionContext save xid * @param userId 用户id * @param money 金额 * @return */ @TwoPhaseBusinessAction(name = "accountApi", commitMethod = "commit", rollbackMethod = "rollback") @RequestMapping("/account/decrease") boolean prepare(@RequestBody BusinessActionContext actionContext, @RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money); /** * Commit boolean. * * @param actionContext save xid * @return the boolean */ @RequestMapping("/account/commit") boolean commit(@RequestBody BusinessActionContext actionContext); /** * Rollback boolean. * * @param actionContext save xid * @return the boolean */ @RequestMapping("/account/rollback") boolean rollback(@RequestBody BusinessActionContext actionContext); }
整个接口的注解有2个，一个是FeignClient，因为服务间采用Feign进行通信，不多说明。第二个就是@LocalTCC，这个就标注了这是一个TCC的分支事务接口类，里面定义了TCC要求的3个方法。尤其强调的是，prepare方法上面要加注解@TwoPhaseBusinessAction，注解里面要指定提交和回滚的方法。
这个接口作为feign客户端，请求发送到了账户服务，账户服务接到对应的请求后分别进行处理。
3.账户服务中controller接到请求后，调用对应的service进行处理，代码如下：
@Service("accountServiceImpl") public class AccountServiceImpl implements AccountService{ private static final Logger LOGGER = LoggerFactory.getLogger(AccountServiceImpl.class); private Map<String, Statement> statementMap = new ConcurrentHashMap<>(100); private Map<String, Connection> connectionMap = new ConcurrentHashMap<>(100); @Resource private DataSource hikariDataSource; @Override public boolean decrease(String xid, Long userId, BigDecimal payAmount) { LOGGER.info("commit, xid:{}", xid); LOGGER.info("------->尝试扣减账户开始account"); //模拟超时异常，全局事务回滚 /*try { Thread.sleep(30*1000); } catch (InterruptedException e) { e.printStackTrace(); }*/ try { //尝试扣减账户金额,事务不提交 Connection connection = hikariDataSource.getConnection(); connection.setAutoCommit(false); String sql = "UPDATE account SET balance = balance - ?,used = used + ? where user_id = ?"; PreparedStatement stmt = connection.prepareStatement(sql); stmt.setBigDecimal(1, payAmount); stmt.setBigDecimal(2, payAmount); stmt.setLong(3, userId); stmt.executeUpdate(); statementMap.put(xid, stmt); connectionMap.put(xid, connection); } catch (Exception e) { LOGGER.error("decrease parepare failure:", e); return false; } LOGGER.info("------->尝试扣减账户结束account"); return true; } public boolean commit(String xid){ LOGGER.info("扣减账户金额, commit, xid:{}", xid); PreparedStatement statement = (PreparedStatement) statementMap.get(xid); Connection connection = connectionMap.get(xid); try { if (null != connection){ connection.commit(); } } catch (SQLException e) { LOGGER.error("扣减账户失败:", e); return false; }finally { try { statementMap.remove(xid); connectionMap.remove(xid); if (null != statement){ statement.close(); } if (null != connection){ connection.close(); } } catch (SQLException e) { LOGGER.error("扣减账户提交事务后关闭连接池失败:", e); } } return true; } public boolean rollback(String xid){ LOGGER.info("扣减账户金额, rollback, xid:{}", xid); PreparedStatement statement = (PreparedStatement) statementMap.get(xid); Connection connection = connectionMap.get(xid); try { connection.rollback(); } catch (SQLException e) { return false; }finally { try { if (null != statement){ statement.close(); } if (null != connection){ connection.close(); } statementMap.remove(xid); connectionMap.remove(xid); } catch (SQLException e) { LOGGER.error("扣减账户回滚事务后关闭连接池失败:", e); } } return true; } }
从上面的代码中我们可以看到，我们使用了jdbc进行了事务管理，prepare方法缓存了Statement和Connection，commit和rollback方法进行事务的提交和回滚，然后释放连接。
实验结果
启动eureka server，seata server，然后启动上面3个服务。
运行之前，我们先看一下数据库的数据，seata_order库中orders表没有数据，seata_pay库中account表和seata_storage库中storage表数据如下图：
1.模拟commit事务
服务启动后，我们用postman发一个post请求，请求url:http://localhost:8180/order/create,请求参数：
{ "userId":1, "productId":1, "count":1, "money":1, "payAmount":50 }
请求成功后，我们查看上面3张表的数据，如下图：
可以看到，数据已经提交成功了。这时我们查看一下order-server日志:
2020-08-23 10:13:00.187 INFO 638408 --- [nio-8180-exec-1] io.seata.tm.TransactionManagerHolder : TransactionManager Singleton io.seata.tm.DefaultTransactionManager@2501a5fc 2020-08-23 10:13:00.207 INFO 638408 --- [nio-8180-exec-1] i.seata.tm.api.DefaultGlobalTransaction : Begin new global transaction [192.168.59.132:8091:41466478607220736] 2020-08-23 10:13:00.212 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->交易开始 2020-08-23 10:13:00.232 INFO 638408 --- [nio-8180-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2020-08-23 10:13:00.431 INFO 638408 --- [nio-8180-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. 2020-08-23 10:13:00.445 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->扣减库存开始storage中 2020-08-23 10:13:00.645 INFO 638408 --- [nio-8180-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: storage-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647 2020-08-23 10:13:00.899 INFO 638408 --- [nio-8180-exec-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-storage-server 2020-08-23 10:13:00.900 INFO 638408 --- [nio-8180-exec-1] c.netflix.loadbalancer.BaseLoadBalancer : Client: storage-server instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=storage-server,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null 2020-08-23 10:13:00.906 INFO 638408 --- [nio-8180-exec-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater 2020-08-23 10:13:00.938 INFO 638408 --- [nio-8180-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: storage-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647 2020-08-23 10:13:00.941 INFO 638408 --- [nio-8180-exec-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client storage-server initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=storage-server,current list of Servers=[10.192.86.60:8182],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;] },Server stats: [[Server:10.192.86.60:8182; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 08:00:00 CST 1970; First connection made: Thu Jan 01 08:00:00 CST 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0] ]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@50d8d3a7 2020-08-23 10:13:01.165 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->扣减库存结束storage中 2020-08-23 10:13:01.165 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->扣减账户开始account中 2020-08-23 10:13:01.211 INFO 638408 --- [nio-8180-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: account-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647 2020-08-23 10:13:01.212 INFO 638408 --- [nio-8180-exec-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-account-server 2020-08-23 10:13:01.212 INFO 638408 --- [nio-8180-exec-1] c.netflix.loadbalancer.BaseLoadBalancer : Client: account-server instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=account-server,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null 2020-08-23 10:13:01.213 INFO 638408 --- [nio-8180-exec-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater 2020-08-23 10:13:01.214 INFO 638408 --- [nio-8180-exec-1] c.netflix.config.ChainedDynamicProperty : Flipping property: account-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647 2020-08-23 10:13:01.215 INFO 638408 --- [nio-8180-exec-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client account-server initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=account-server,current list of Servers=[10.192.86.60:8181],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;] },Server stats: [[Server:10.192.86.60:8181; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 08:00:00 CST 1970; First connection made: Thu Jan 01 08:00:00 CST 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0] ]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@7145f1b9 2020-08-23 10:13:01.640 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->扣减账户结束account中true 2020-08-23 10:13:01.641 INFO 638408 --- [nio-8180-exec-1] i.seata.sample.service.OrderServiceImpl : ------->交易结束 2020-08-23 10:13:01.648 INFO 638408 --- [ch_RMROLE_1_1_8] i.s.c.r.p.c.RmBranchCommitProcessor : rm client handle branch commit process:xid=192.168.59.132:8091:41466478607220736,branchId=41466478707884032,branchType=TCC,resourceId=orderApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321580213,"host-name":"10.192.254.57","sys::prepare":"saveOrder","actionName":"orderApi"}} 2020-08-23 10:13:01.651 INFO 638408 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractRMHandler : Branch committing: 192.168.59.132:8091:41466478607220736 41466478707884032 orderApi {"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321580213,"host-name":"10.192.254.57","sys::prepare":"saveOrder","actionName":"orderApi"}} 2020-08-23 10:13:01.652 INFO 638408 --- [ch_RMROLE_1_1_8] io.seata.sample.service.OrderSaveImpl : 保存订单, commit, xid:192.168.59.132:8091:41466478607220736 2020-08-23 10:13:01.657 INFO 638408 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractResourceManager : TCC resource commit result : true, xid: 192.168.59.132:8091:41466478607220736, branchId: 41466478707884032, resourceId: orderApi 2020-08-23 10:13:01.659 INFO 638408 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractRMHandler : Branch commit result: PhaseTwo_Committed 2020-08-23 10:13:01.664 INFO 638408 --- [ch_RMROLE_1_2_8] i.s.c.r.p.c.RmBranchCommitProcessor : rm client handle branch commit process:xid=192.168.59.132:8091:41466478607220736,branchId=41466479647408128,branchType=TCC,resourceId=storageApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321580446,"host-name":"10.192.254.57","sys::prepare":"decrease","actionName":"storageApi"}} 2020-08-23 10:13:01.664 INFO 638408 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractRMHandler : Branch committing: 192.168.59.132:8091:41466478607220736 41466479647408128 storageApi {"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321580446,"host-name":"10.192.254.57","sys::prepare":"decrease","actionName":"storageApi"}} 2020-08-23 10:13:01.677 INFO 638408 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractResourceManager : TCC resource commit result : true, xid: 192.168.59.132:8091:41466478607220736, branchId: 41466479647408128, resourceId: storageApi 2020-08-23 10:13:01.677 INFO 638408 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractRMHandler : Branch commit result: PhaseTwo_Committed 2020-08-23 10:13:01.680 INFO 638408 --- [ch_RMROLE_1_3_8] i.s.c.r.p.c.RmBranchCommitProcessor : rm client handle branch commit process:xid=192.168.59.132:8091:41466478607220736,branchId=41466482671501312,branchType=TCC,resourceId=accountApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321581166,"host-name":"10.192.254.57","sys::prepare":"prepare","actionName":"accountApi"}} 2020-08-23 10:13:01.680 INFO 638408 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractRMHandler : Branch committing: 192.168.59.132:8091:41466478607220736 41466482671501312 accountApi {"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598321581166,"host-name":"10.192.254.57","sys::prepare":"prepare","actionName":"accountApi"}} 2020-08-23 10:13:01.695 INFO 638408 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractResourceManager : TCC resource commit result : true, xid: 192.168.59.132:8091:41466478607220736, branchId: 41466482671501312, resourceId: accountApi 2020-08-23 10:13:01.695 INFO 638408 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractRMHandler : Branch commit result: PhaseTwo_Committed 2020-08-23 10:13:01.702 INFO 638408 --- [nio-8180-exec-1] i.seata.tm.api.DefaultGlobalTransaction : [192.168.59.132:8091:41466478607220736] commit status: Committed 2020-08-23 10:13:01.911 INFO 638408 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty : Flipping property: storage-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647 2020-08-23 10:13:02.215 INFO 638408 --- [erListUpdater-1] c.netflix.config.ChainedDynamicProperty : Flipping property: account-server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
仔细查看这段日志，我们发现有3个2阶段提交成功(PhaseTwo_Committed)，resourceId分别是orderApi、storageApi和accountApi，而在库存服务和账户服务也分别有相关日志的打印，如下：
2020-08-23 10:13:01.123 INFO 645052 --- [nio-8182-exec-3] i.s.sample.service.StorageServiceImpl : ------->扣减库存prepare开始 2020-08-23 10:13:01.135 INFO 645052 --- [nio-8182-exec-3] i.s.sample.service.StorageServiceImpl : ------->扣减库存prepare结束 2020-08-23 10:13:01.150 WARN 645052 --- [nio-8182-exec-3] c.a.c.seata.web.SeataHandlerInterceptor : xid in change during RPC from 192.168.59.132:8091:41466478607220736 to null 2020-08-23 10:13:01.672 INFO 645052 --- [nio-8182-exec-4] i.s.sample.service.StorageServiceImpl : 扣减库存金额, commit, xid:192.168.59.132:8091:41466478607220736
2020-08-23 10:13:01.358 INFO 643544 --- [nio-8181-exec-1] i.s.sample.service.AccountServiceImpl : ------->尝试扣减账户开始account 2020-08-23 10:13:01.358 INFO 643544 --- [nio-8181-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2020-08-23 10:13:01.606 INFO 643544 --- [nio-8181-exec-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. 2020-08-23 10:13:01.623 INFO 643544 --- [nio-8181-exec-1] i.s.sample.service.AccountServiceImpl : ------->尝试扣减账户结束account 2020-08-23 10:13:01.638 WARN 643544 --- [nio-8181-exec-1] c.a.c.seata.web.SeataHandlerInterceptor : xid in change during RPC from 192.168.59.132:8091:41466478607220736 to null 2020-08-23 10:13:01.686 INFO 643544 --- [nio-8181-exec-2] i.s.sample.service.AccountServiceImpl : 扣减账户金额, commit, xid:192.168.59.132:8091:41466478607220736
2.模拟rollback事务
修改OrderServiceImpl中create方法，最后一行代码改为如下：
throw new RuntimeException("调用2阶段提交的rollback方法"); //return true
重启服务后，我们再次模拟发送上面的post请求，参数不变，这时查看order-server的日志如下：
前面的日志都一样，我们看一下回滚日志：
2020-08-23 10:54:54.209 INFO 652376 --- [ch_RMROLE_1_1_8] i.s.c.r.p.c.RmBranchRollbackProcessor : rm handle branch rollback process:xid=192.168.59.132:8091:41477018662486016,branchId=41477022726766592,branchType=TCC,resourceId=accountApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598324094118,"host-name":"10.192.254.57","sys::prepare":"prepare","actionName":"accountApi"}} 2020-08-23 10:54:54.212 INFO 652376 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractRMHandler : Branch Rollbacking: 192.168.59.132:8091:41477018662486016 41477022726766592 accountApi 2020-08-23 10:54:54.247 INFO 652376 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractResourceManager : TCC resource rollback result : true, xid: 192.168.59.132:8091:41477018662486016, branchId: 41477022726766592, resourceId: accountApi 2020-08-23 10:54:54.249 INFO 652376 --- [ch_RMROLE_1_1_8] io.seata.rm.AbstractRMHandler : Branch Rollbacked result: PhaseTwo_Rollbacked 2020-08-23 10:54:54.258 INFO 652376 --- [ch_RMROLE_1_2_8] i.s.c.r.p.c.RmBranchRollbackProcessor : rm handle branch rollback process:xid=192.168.59.132:8091:41477018662486016,branchId=41477020038217728,branchType=TCC,resourceId=storageApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598324093476,"host-name":"10.192.254.57","sys::prepare":"decrease","actionName":"storageApi"}} 2020-08-23 10:54:54.258 INFO 652376 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractRMHandler : Branch Rollbacking: 192.168.59.132:8091:41477018662486016 41477020038217728 storageApi 2020-08-23 10:54:54.301 INFO 652376 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractResourceManager : TCC resource rollback result : true, xid: 192.168.59.132:8091:41477018662486016, branchId: 41477020038217728, resourceId: storageApi 2020-08-23 10:54:54.301 INFO 652376 --- [ch_RMROLE_1_2_8] io.seata.rm.AbstractRMHandler : Branch Rollbacked result: PhaseTwo_Rollbacked 2020-08-23 10:54:54.306 INFO 652376 --- [ch_RMROLE_1_3_8] i.s.c.r.p.c.RmBranchRollbackProcessor : rm handle branch rollback process:xid=192.168.59.132:8091:41477018662486016,branchId=41477018775732224,branchType=TCC,resourceId=orderApi,applicationData={"actionContext":{"sys::rollback":"rollback","sys::commit":"commit","action-start-time":1598324093164,"host-name":"10.192.254.57","sys::prepare":"saveOrder","actionName":"orderApi"}} 2020-08-23 10:54:54.306 INFO 652376 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractRMHandler : Branch Rollbacking: 192.168.59.132:8091:41477018662486016 41477018775732224 orderApi 2020-08-23 10:54:54.307 INFO 652376 --- [ch_RMROLE_1_3_8] io.seata.sample.service.OrderSaveImpl : 保存订单金额, rollback, xid:192.168.59.132:8091:41477018662486016 2020-08-23 10:54:54.316 INFO 652376 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractResourceManager : TCC resource rollback result : true, xid: 192.168.59.132:8091:41477018662486016, branchId: 41477018775732224, resourceId: orderApi 2020-08-23 10:54:54.316 INFO 652376 --- [ch_RMROLE_1_3_8] io.seata.rm.AbstractRMHandler : Branch Rollbacked result: PhaseTwo_Rollbacked 2020-08-23 10:54:54.336 INFO 652376 --- [nio-8180-exec-1] i.seata.tm.api.DefaultGlobalTransaction : [192.168.59.132:8091:41477018662486016] rollback status: Rollbacked 2020-08-23 10:54:54.353 ERROR 652376 --- [nio-8180-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.RuntimeException: 调用2阶段提交的rollback方法] with root cause java.lang.RuntimeException: 调用2阶段提交的rollback方法 at io.seata.sample.service.OrderServiceImpl.create(OrderServiceImpl.java:65) ~[classes/:na]
可以看出，上面有3个2阶段的事务回滚(PhaseTwo_Rollbacked),resourceId分别是orderApi、storageApi和accountApi,这时我们再看库存服务和账户服务的日志，如下：
2020-08-23 10:54:54.101 INFO 645052 --- [nio-8182-exec-2] i.s.sample.service.StorageServiceImpl : ------->扣减库存prepare开始 2020-08-23 10:54:54.103 INFO 645052 --- [nio-8182-exec-2] i.s.sample.service.StorageServiceImpl : ------->扣减库存prepare结束 2020-08-23 10:54:54.105 WARN 645052 --- [nio-8182-exec-2] c.a.c.seata.web.SeataHandlerInterceptor : xid in change during RPC from 192.168.59.132:8091:41477018662486016 to null
2020-08-23 10:54:54.189 INFO 643544 --- [nio-8181-exec-4] i.s.sample.service.AccountServiceImpl : ------->尝试扣减账户开始account 2020-08-23 10:54:54.191 INFO 643544 --- [nio-8181-exec-4] i.s.sample.service.AccountServiceImpl : ------->尝试扣减账户结束account 2020-08-23 10:54:54.192 WARN 643544 --- [nio-8181-exec-4] c.a.c.seata.web.SeataHandlerInterceptor : xid in change during RPC from 192.168.59.132:8091:41477018662486016 to null 2020-08-23 10:54:54.223 INFO 643544 --- [nio-8181-exec-5] i.s.sample.service.AccountServiceImpl : 扣减账户金额, rollback, xid:192.168.59.132:8091:41477018662486016
这时我们再查看数据库，3张表都没有变。可见事务确实做了回滚。
总结
分布式事务的TCC模式和AT模式的本质区别是一个是2阶段提交，一个是交易补偿。seata框架对AT模式的支持是非常方便的，但是对TCC模式的支持，最大的就是自动触发commit和prepare方法，真正的实现还是需要开发人员自己做。
大家有更好的实现2阶段事务提交的方法，欢迎指点。
