1、Demo项目依赖

  • springboot-2.4.7
  • spring-cloud 2020.0.1
  • spring-cloud-alibaba 2.21.1
  • openfeign 3.0.1
  • seata 1.4.2
  • spring-cloud-starter-alibaba-nacos-discovery 2.21.1

  • mybatis-springboot-starter 2.1.2

    2、Demo案例设计

    本demo设计了一个转账交易的业务场景，分为两个部分，第一部分是本地调用取款服务，第二部分是远程调用存款服务，远程调用通过FeignClient实现，以nacos做注册中心，以seata支持分布式事务，使用本地配置。
    【QuickStart】Seata-TCC与springboot、Feign集成 - 图1

    3、Demo工程搭建

    搭建Springboot项目，并引入相关依赖，分别搭建2个项目demo01和demo02，并启动一个seata-server实例，启动一个nacos实例。

  • demo的配置文件application.yml如下： ```java server: port: 8081

spring: application: name: seata-demo-01 datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://139.198.170.206:3306/seata-demo-bank01?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8 username: root password: Xw159753. cloud: nacos: discovery: server-addr: 139.198.170.206:8848 group: SEATA_GROUP namespace: b0e7a06f-af32-436b-97c0-1639e7e03b49

seata: enabled: true application-id: ${spring.application.name} enable-auto-data-source-proxy: true tx-service-group: seata-demo-01-group registry: type: nacos nacos: server-addr: 139.198.170.206:8848 group: SEATA_GROUP namespace: b0e7a06f-af32-436b-97c0-1639e7e03b49 username: “” password: “” config: type: file file: name: file.conf

logging: level: io: seata: info

mybatis: mapperLocations: classpath:mapper/.xml configuration: map-underscore-to-camel-case: true

log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

  2. - demo中seata的配置文件file.conf如下：
  3. ```java
  4. transport {
  5.   # tcp udt unix-domain-socket
  6.   type = "TCP"
  7.   #NIO NATIVE
  8.   server = "NIO"
  9.   #enable heartbeat
  10.   heartbeat = true
  11.   # the client batch send request enable
  12.   enableClientBatchSendRequest = true
  13.   #thread factory for netty
  14.   threadFactory {
  15.     bossThreadPrefix = "NettyBoss"
  16.     workerThreadPrefix = "NettyServerNIOWorker"
  17.     serverExecutorThread-prefix = "NettyServerBizHandler"
  18.     shareBossWorker = false
  19.     clientSelectorThreadPrefix = "NettyClientSelector"
  20.     clientSelectorThreadSize = 1
  21.     clientWorkerThreadPrefix = "NettyClientWorkerThread"
  22.     # netty boss thread size,will not be used for UDT
  23.     bossThreadSize = 1
  24.     #auto default pin or 8
  25.     workerThreadSize = "default"
  26.   }
  27.   shutdown {
  28.     # when destroy server, wait seconds
  29.     wait = 3
  30.   }
  31.   serialization = "seata"
  32.   compressor = "none"
  33. }
  35. service {
  36.   #transaction service group mapping
  37.   #该配置项要与seata-server的cluster配置项的值一样
  38.   vgroupMapping.seata-demo-01-group = "bank-demo"
  39.   #only support when registry.type=file, please don't set multiple addresses
  40.   default.grouplist = "127.0.0.1:8091"
  41.   #degrade, current not support
  42.   enableDegrade = false
  43.   #disable seata
  44.   disableGlobalTransaction = false
  45. }
  47. client {
  48.   rm {
  49.     asyncCommitBufferLimit = 10000
  50.     lock {
  51.       retryInterval = 10
  52.       retryTimes = 30
  53.       retryPolicyBranchRollbackOnConflict = true
  54.     }
  55.     reportRetryCount = 5
  56.     tableMetaCheckEnable = false
  57.     reportSuccessEnable = false
  58.   }
  59.   tm {
  60.     commitRetryCount = 5
  61.     rollbackRetryCount = 5
  62.   }
  63.   undo {
  64.     dataValidation = true
  65.     logSerialization = "jackson"
  66.     logTable = "undo_log"
  67.   }
  68.   log {
  69.     exceptionRate = 100
  70.   }
  71. }

4、Demo业务场景开发

采用经典的springMVC架构，在AccountCotroller中暴露服务接口，在Service中编写服务逻辑，在mapper中进行数据库交互。重点不同的是，需要开发seata-tcc相关的接口。

  • 工程结构如下：

image.png

4.1、开发AccountTccAction接口和实现

  • AccountTccAction接口如下：

    1. @LocalTCC
    2. public interface AccountTccAction {
    3.   /**
    4.    * 取款
    5.    * 使用 @BusinessActionContextParameter 注解的参数数据会被存入 BusinessActionContext
    6.    * @param businessActionContext BusinessActionContext 上下文对象，用来在两个阶段之间传递数据
    7.    * @param accountId
    8.    * @param money
    9.    * @return
    10.    */
    11.   @TwoPhaseBusinessAction(name = "fetchBalanceTcc",commitMethod = "fetchBalanceCommit",rollbackMethod = "fetchBalanceRollback")
    12.   public String fetchBalanceTry(BusinessActionContext businessActionContext,
    13.                                 @BusinessActionContextParameter(paramName = "accountId") String accountId,
    14.                                 @BusinessActionContextParameter(paramName = "money") int money);
    15.   /**
    16.    * 取款服务 二阶段提交
    17.    * @param businessActionContext
    18.    */
    19.   public void fetchBalanceCommit(BusinessActionContext businessActionContext);
    20.   /**
    21.    * 取款服务 二阶段回滚
    22.    * @param businessActionContext
    23.    */
    24.   public void fetchBalanceRollback(BusinessActionContext businessActionContext);
    25. }

  • AccountTccActionImpl实现类如下：

    1. @Service
    2. public class AccountTccActionImpl implements AccountTccAction {
    3.   private static final Logger log = LoggerFactory.getLogger(AccountService.class);
    5.   @Autowired
    6.   AccountMapper accountMapper;
    7.   @Autowired
    8.   AccountServiceFeign accountServiceFeign;
    10.   @Override
    11.   public String fetchBalanceTry(BusinessActionContext businessActionContext, String accountId, int money) {
    12.       Account  account = accountMapper.getAccountInfoById(accountId);
    13.       int balance = account.getBalance() - money;
    14.       accountMapper.transformMoney(accountId,balance);
    15.       return "取款成功，账户余额："+balance;
    16.   }
    18.   @Override
    19.   public void fetchBalanceCommit(BusinessActionContext businessActionContext) {
    20.       //为了演示，仅打印日志，并未进行实际的业务二次提交操作
    21.       String accountId = (String)businessActionContext.getActionContext("accountId");
    22.       int money = (int) businessActionContext.getActionContext("money");
    23.       log.info(">>>>>>>>>>>>>fetchBalanceCommit running, accountId:{}, money:{}",accountId,money);
    24.   }
    26.   @Override
    27.   public void fetchBalanceRollback(BusinessActionContext businessActionContext) {
    28.       //为了演示，仅打印日志，并未进行实际的业务回滚操作
    29.       String accountId = (String)businessActionContext.getActionContext("accountId");
    30.       int money = (int) businessActionContext.getActionContext("money");
    31.       log.info(">>>>>>>>>>>>>fetchBalanceRollback running, accountId:{}, money:{}",accountId,money);
    32.   }
    33. }

    4.2、开发远程调用的FeignClient

  • AccountServiceFeign如下： ```java @FeignClient(value = “seata-demo-02”, path = “/account”) @LocalTCC public interface AccountServiceFeign { /**

    • 存款
    • 使用 @BusinessActionContextParameter 注解标注的参数会自动注入到businessActionContext中
    • @param accountId
    • @param money
    • @return */ @RequestMapping(“/depositBalance”) @TwoPhaseBusinessAction(name = “remoteDepositBalance”,commitMethod = “remoteDepositBalanceCommit”,rollbackMethod = “remoteDepositBalanceRollback”) public String remoteDepositBalance(@RequestBody BusinessActionContext businessActionContext,
      1.                             @BusinessActionContextParameter(paramName = "accountId") @RequestParam("accountId")String accountId,
      2.                             @BusinessActionContextParameter(paramName = "money") @RequestParam("money")int money);
      @RequestMapping(“/depositBalanceCommit”) public Boolean remoteDepositBalanceCommit(@RequestBody BusinessActionContext businessActionContext); @RequestMapping(“/depositBalanceRollback”) public Boolean remoteDepositBalanceRollback(@RequestBody BusinessActionContext businessActionContext);

}

  1. <a name="ZPXiJ"></a>
  2. ## 4.3、在业务代码中调用转账服务，并开启全局事务
  4. - AccountService如下：
  5. ```java
  6. @Service
  7. public class AccountService {
  8.     private static final Logger log = LoggerFactory.getLogger(AccountService.class);
  9.     @Autowired
  10.     AccountServiceFeign accountServiceFeign;
  11.     @Autowired
  12.     AccountTccAction accountTccAction;
  14.     /**
  15.      * 远程转账 使用LocalTcc模式
  16.      * @param localAccountIdSrc
  17.      * @param remoteAccountIdDest
  18.      * @param money
  19.      * @return
  20.      */
  21.     @GlobalTransactional
  22.     public String remoteTransformMoneyTcc(String localAccountIdSrc,String remoteAccountIdDest, int money){
  23.         //本地取款
  24.         accountTccAction.fetchBalanceTry(null,localAccountIdSrc,money);
  25.         //远程调用存款
  26.         String result = accountServiceFeign.remoteDepositBalance(null,remoteAccountIdDest,money);
  27.         return result;
  28.     }

4.4、在Controller中暴露转账接口

  • AccountController如下：

    1. @RestController
    2. @RequestMapping(value="/account")
    3. public class AccountController {
    4.   @Autowired
    5.   AccountService accountService;
    7.   /**
    8.    * 跨行转账，使用Tcc模式
    9.    * @param localAccountIdSrc
    10.    * @param remoteAccountIdDest
    11.    * @param money
    12.    * @return
    13.    */
    14.   @RequestMapping("/remoteTransformMoneyTcc")
    15.   public String remoteTransformMoneyTcc(@RequestParam("localAccountIdSrc") String localAccountIdSrc,
    16.                                         @RequestParam("remoteAccountIdDest") String remoteAccountIdDest,
    17.                                         @RequestParam("money")int money){
    18.       return accountService.remoteTransformMoneyTcc(localAccountIdSrc,remoteAccountIdDest,money);
    19.   }

    4.5、远程存款服务开发

  • RemoteAccountController如下： ```java @RestController @RequestMapping(value=”/account”) public class AccountController { private static final Logger log = LoggerFactory.getLogger(AccountController.class); @Autowired AccountService accountService;

    /**

    • 存款 一阶段try
    • @param accountId
    • @param money
    • @return */ @RequestMapping(“/depositBalance”) public String depositBalance(@RequestBody BusinessActionContext businessActionContext,
      1.                       @RequestParam("accountId") String accountId,
      2.                       @RequestParam("money")int money){
      String xid = (String)businessActionContext.getXid(); log.info(“>>>>>>>>>>>>>>>>>>depositBalanceCommit running, xid:{}”,xid); return accountService.depositBalance(accountId,money); } /**
    • 存款 二阶段提交
    • @param businessActionContext
    • @return / @RequestMapping(“/depositBalanceCommit”) public Boolean depositBalanceCommit(@RequestBody BusinessActionContext businessActionContext){ String accountId = (String)businessActionContext.getActionContext(“accountId”); int money = (int)businessActionContext.getActionContext(“money”); String xid = (String)businessActionContext.getXid(); log.info(“>>>>>>>>>>>>>>>>>>depositBalanceCommit running, accountId:{}, money:{}, xid:{}”,accountId,money,xid); return true; } /*
    • 存款 二阶段回滚
    • @param businessActionContext
    • @return */ @RequestMapping(“/depositBalanceRollback”) public Boolean depositBalanceRollback(@RequestBody BusinessActionContext businessActionContext){ String accountId = (String)businessActionContext.getActionContext(“accountId”); int money = (int)businessActionContext.getActionContext(“money”); String xid = (String)businessActionContext.getXid(); log.info(“>>>>>>>>>>>>>>>>>>depositBalanceRollback running, accountId:{}, money:{}, xid:{}”,accountId,money,xid); return true; }

} ```

5、总结

  • @LocalTcc注解必须使用在interface上，不能直接在class上使用，否则不生效
  • BusinessActionContext是seata-tcc模式的上下文，相关业务参数和分布式事务的参数都可以通过该上下文传递
  • 使用@BusinessActionContextParameter(paramName = “accountId”)注解标注的参数，seata会自动注入到上下文BusinessActionContext中
  • 需要使用@GlobalTransactional注解开启全局事务，否则不生效