3LCN-TCC模式 · SpringCloud微服务实战 · 看云

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本节代码地址

GitHub:https://github.com/xuyisu/fw-spring-cloud/tree/master/fw-cloud-transaction/fw-cloud-transaction-lcn/fw-cloud-transaction-lcn-tcc
GitHub:https://github.com/xuyisu/fw-spring-cloud/tree/master/fw-cloud-transaction/fw-cloud-transaction-lcn/fw-cloud-transaction-lcn-txmanager

1、原理介绍:

TCC事务机制相对于传统事务机制（X/Open XA Two-Phase-Commit），其特征在于它不依赖资源管理器(RM)对XA的支持，而是通过对（由业务系统提供的）业务逻辑的调度来实现分布式事务。主要由三步操作，Try: 尝试执行业务、 Confirm:确认执行业务、 Cancel: 取消执行业务。

2、模式特点:

  • 该模式对代码的嵌入性高，要求每个业务需要写三种步骤的操作。
  • 该模式对有无本地事务控制都可以支持使用面广。
  • 数据一致性控制几乎完全由开发者控制，对业务开发难度要求高。

3. 环境准备

中间件 版本
MySQL（可以参照容器化章节） 5.7+
Redis（可以参照容器化章节） 4.0+

3.1 数据库准备

新建fw-txmanager数据库，并且执行以下脚本创建异常表，表名不能变。

CREATE TABLE `t_tx_exception` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `group_id` varchar(64) DEFAULT NULL,
  `unit_id` varchar(32) DEFAULT NULL,
  `mod_id` varchar(128) DEFAULT NULL,
  `transaction_state` tinyint(4) DEFAULT NULL,
  `registrar` tinyint(4) DEFAULT NULL,
  `remark` varchar(4096) DEFAULT NULL,
  `ex_state` tinyint(4) DEFAULT NULL COMMENT '0 未解决 1已解决',
  `create_time` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='tx-manager异常表'

4. 新建TCC 模块

本模块中我们将新建两个模块，我们将模拟电商购物环节中的下单->发货的过程，两个服务通过Feign进行远程调用。两个模块的名称分别为fw-cloud-transaction-lcn-tcc-order和fw-cloud-transaction-lcn-tcc-send

4.1 maven 依赖

两个模块所使用的依赖也是相同的，这里可以看到，我们依赖了上面封装的fw-cloud-transaction-base-dao，不需要再自己写基本的mapper等，因为是基于Eureka 服务发现和Feign 远程调用的，因此引入了响应的包。其中最重要的就是引入txlcn-tc，txlcn-txmsg-netty包，否者不能实现和TxManager的通信及事务控制。

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- base-dao -->
    <dependency>
        <groupId>com.yisu.cloud</groupId>
        <artifactId>fw-cloud-transaction-base-dao</artifactId>
        <version>${version}</version>
    </dependency>
    <!-- TC依赖 -->
    <dependency>
        <groupId>com.codingapi.txlcn</groupId>
        <artifactId>txlcn-tc</artifactId>
    </dependency>
    <!-- TC和TM通信依赖于Netty -->
    <dependency>
        <groupId>com.codingapi.txlcn</groupId>
        <artifactId>txlcn-txmsg-netty</artifactId>
    </dependency>
    <!--服务发现-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!--feign-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <!-- 数据连接池-->
    <dependency>
        <groupId>com.zaxxer</groupId>
        <artifactId>HikariCP</artifactId>
        <version>${HikariCP.version}</version>
    </dependency>
</dependencies>

并在MySql中新建fw_transaction库,并执行以下脚本，供fw-cloud-transaction-lcn-tcc-order和fw-cloud-transaction-lcn-tcc-send使用

CREATE TABLE `fw_trade_log` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0' COMMENT '订单状态 1.待支付 2.待发货 3.待收货 4.订单完成 5.订单关闭',
  `status_dsc` varchar(100) CHARACTER SET utf8 DEFAULT '' COMMENT '状态描述',
  `product_id` bigint(20) NOT NULL DEFAULT '0' COMMENT '商品id',
  `product_name` varchar(100) NOT NULL DEFAULT '' COMMENT '商品名称',
  `user_id` bigint(20) NOT NULL DEFAULT '0' COMMENT '用户id',
  `order_id` bigint(20) NOT NULL DEFAULT '0' COMMENT '订单id',
  `order_amount` decimal(10,2) NOT NULL DEFAULT '0.00' COMMENT '订单总额',
  `create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '创建时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='订单表'

4.2 fw-cloud-transaction-lcn-tcc-order模块

4.2.1 订单接口创建

再订单模块中创建一个订单接口，并在接口中设置支付成功的方法


public interface OrderService{

    
    void saveAndPayOrder(String productName);

}

4.2.2 订单接口实现

订单在支付成功以后会远程调用发货服务进行发货，需要在Service 上加上@TccTransaction，开启TCC模式的分布式事务控制，并且设置订单的状态为待支付，然后编写confirm和cancel 方法，规则是confirm\cancel+业务方法名


@Service
@Slf4j
public class OrderServiceImpl implements OrderService {

    @Autowired
    private FwTradeLogService fwTradeLogService;

    @Autowired
    private RemoteSendServiceFeign remoteSendServiceFeign;


    ConcurrentHashMap<String, Long> hashMap = new ConcurrentHashMap<>();

    @TccTransaction
    @Override
    public void saveAndPayOrder(String productName) {

        FwTradeLog fwTradeLog =new FwTradeLog(StatusEnum.TWO);
        fwTradeLog.setProductId(System.currentTimeMillis());
        fwTradeLog.setProductName(productName);
        fwTradeLogService.save(fwTradeLog);
        log.info("[订单状态{}]=>{},当前商品id=>{},商品名称=>{}",fwTradeLog.getOrderId(), StatusEnum.TWO.getDesc(),fwTradeLog.getProductId(),fwTradeLog.getProductName());

        remoteSendServiceFeign.sendOrder(fwTradeLog);
        hashMap.put(TracingContext.tracing().groupId(), fwTradeLog.getId());
        
    }

    public void confirmSaveAndPayOrder(String productName){
        log.info("当前产品{},事务执行成功",productName);
        hashMap.remove(TracingContext.tracing().groupId());
    }

    public void cancelSaveAndPayOrder(String productName){
        Long tradeLogId = hashMap.get(TracingContext.tracing().groupId());
        log.info("当前产品{},事务执行失败，回滚tradeLogId为{}的数据", productName,tradeLogId);
        fwTradeLogService.removeById(tradeLogId);
        hashMap.remove(TracingContext.tracing().groupId());
    }

}

4.2.3 Feign 接口配置

这里我们配置远程调用的服务名称是fw-transaction-lcn-tcc-send，并且设置了fallback，并且指定了远程调用的方法是sendOrder。

@FeignClient(value = "fw-transaction-lcn-tcc-send", fallbackFactory = RemoteSendServiceFallback.class)
public interface RemoteSendServiceFeign {

    @PostMapping("send")
    void sendOrder(@RequestBody  FwTradeLog tradeLog);
}

4.2.4 Fallback 接口配置

在fallback输出异常日志

@Component
@Slf4j
public class RemoteSendServiceFallback implements FallbackFactory<RemoteSendServiceFeign> {

    @Override
    public RemoteSendServiceFeign create(Throwable throwable) {

        return tradeLog -> log.error("远程调用失败",throwable);
    }
}

4.2.5 Controller 控制层

配置订单服务对外的接口，方便演示


@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;

    
    @GetMapping("saveOrder")
    public FwResult saveOrder(String productName){
         orderService.saveAndPayOrder(productName);
         return FwResult.ok();
    }


}

4.2.6 启动类配置

这里需要加上@EnableDistributedTransaction开启分布式的调用，加上@EnableFeignClients开启Feign的远程调用，加上@EnableDiscoveryClient开启服务的注册和发现。

@EnableDistributedTransaction
@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
public class FwTransactionLcnTccOrderApplication {
    public static void main(String[] args) {
        SpringApplication.run(FwTransactionLcnOrderApplication.class, args);
    }


}

4.2.7 应用配置

配置中需要配置数据库和Redis的基本信息，以及TxManager的连接信息，并且设置了Eureka的连接信息和开启Feign的远程调用

server:
  port: 9002
spring:
  application:
    name: fw-transaction-lcn-tcc-order
  #数据库配置  start
  datasource:
    type: com.zaxxer.hikari.HikariDataSource
    url: jdbc:mysql://${dbIp}:3306/fw_transaction?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&useSSL=false
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
    hikari:
      connection-timeout: 20000
      auto-commit: true
      max-lifetime: 1200000
      minimum-idle: 5
      maximum-pool-size: 12
      idle-timeout: 300000
  redis:
    port: 6379
    host: ${redisIp}
    database: 0
    password: 123456
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
tx-lcn:
  client:
    manager-address: 127.0.0.1:8888
  logger:
    enabled: true
feign:
  hystrix:
    enabled: true
hystrix:
  shareSecurityContext: true #设置为true，这样做会自动配置Hystrix并发策略插件挂钩，将SecurityContext从主线程传输到Hystrix命令使用的线程

4.3 fw-cloud-transaction-lcn-tcc-send模块

4.3.1 发货接口创建

配置发货接口，并且创建发货的方法


public interface SendService {

    
    void sendOrder(FwTradeLog fwTradeLog);

}

4.3.2 发货接口实现

这里在实现方法上加上@TccTransaction，并且设置订单的状态为待收货，然后编写confirm和cancel 方法，规则是confirm\cancel+业务方法名


@Service
@Slf4j
public class SendServiceImpl implements SendService {

    @Autowired
    private FwTradeLogService fwTradeLogService;
    ConcurrentHashMap<String, Long> hashMap = new ConcurrentHashMap<>();

    @TccTransaction
    @Override
    public void sendOrder(FwTradeLog fwTradeLog) {
        fwTradeLog.setStatus(StatusEnum.THREE.getValue());
        fwTradeLog.setStatusDsc(StatusEnum.THREE.getDesc());
        fwTradeLogService.save(fwTradeLog);
        log.info("[订单状态{}]=>{},当前商品id=>{},商品名称=>{}",fwTradeLog.getOrderId(), StatusEnum.THREE.getDesc(),fwTradeLog.getProductId(),fwTradeLog.getProductName());
        hashMap.put(TracingContext.tracing().groupId(), fwTradeLog.getId());
    }

    public void confirmSendOrder(FwTradeLog fwTradeLog){
        log.info("当前产品{},事务执行成功",fwTradeLog.getProductName());
        hashMap.remove(TracingContext.tracing().groupId());
    }

    public void cancelSendOrder(FwTradeLog fwTradeLog){
        Long tradeLogId = hashMap.get(TracingContext.tracing().groupId());
        log.info("当前产品{},事务执行失败，回滚tradeLogId为{}的数据", fwTradeLog.getProductName(),tradeLogId);
        fwTradeLogService.removeById(tradeLogId);
        hashMap.remove(TracingContext.tracing().groupId());
    }
}

4.3.3 发货控制层实现

提供给订单模块调用的接口，注意方法名和请求方式要保持一致


@RestController
public class SendController {

    @Autowired
    private SendService sendService;

    
    @PostMapping("send")
    public void sendOrder(@RequestBody FwTradeLog tradeLog) {
         sendService.sendOrder(tradeLog);
    }
}

4.3.4 启动类

需要加上@EnableDistributedTransaction注解开启分布式事务，加上@EnableDiscoveryClient注解开启服务的注册与发现


@EnableDistributedTransaction
@SpringBootApplication
@EnableDiscoveryClient
public class FwTransactionLcnTccSendApplication {
    public static void main(String[] args) {
        SpringApplication.run(FwTransactionLcnSendApplication.class, args);
    }


}

4.3.5 应用配置

配置中需要配置数据库和Redis的基本信息，以及TxManager的连接信息，并且设置了Eureka的连接信息和开启Feign的远程调用

server:
  port: 9003
spring:
  application:
    name: fw-transaction-lcn-tcc-send
  #数据库配置  start
  datasource:
    type: com.zaxxer.hikari.HikariDataSource
    url: jdbc:mysql://${dbIp}:3306/fw_transaction?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&useSSL=false
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
    hikari:
      connection-timeout: 20000
      auto-commit: true
      max-lifetime: 1200000
      minimum-idle: 5
      maximum-pool-size: 12
      idle-timeout: 300000
  redis:
    port: 6379
    host: ${redisIp}
    database: 0
    password: 123456
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
tx-lcn:
  client:
    manager-address: 127.0.0.1:8888

4.4 启动服务

分别启动Eureka、fw-transaction-lcn-tcc-send、fw-transaction-lcn-tcc-order
29370f88262321b6cc4ffc66d37fcb49_MD5.png

TxManager 可以看到两个事务注册上来
659040ec6b1d9d4ce1a41306a8873294_MD5.png

Postman输入localhost:9002/saveOrder
af1cea21c04c3aca13756054649dac97_MD5.png

可以看到订单服务的日志如下

2020-04-06 19:29:22.292  INFO 3829 --- [nio-9002-exec-1] c.y.t.l.o.service.impl.OrderServiceImpl  : [订单状态348582]=>待发货,当前商品id=>1586094502191,商品名称=>Mac pro 2019款

发货服务的日志如下

2020-04-06 19:29:23.202  INFO 3841 --- [nio-9003-exec-1] c.y.t.l.s.service.impl.SendServiceImpl   : [订单状态348582]=>待收货,当前商品id=>1586094502191,商品名称=>Mac pro 2019款

数据库记录两条记录
c0479f4ced6ccd964c1c57292defc86e_MD5.png

现在让订单服务的方法抛出异常
直接在方法中加一个抛异常的语句int i=1/0;，如下所示

@TccTransaction
@Override
public void saveAndPayOrder(String productName) {

    FwTradeLog fwTradeLog =new FwTradeLog(StatusEnum.TWO);
    fwTradeLog.setProductId(System.currentTimeMillis());
    fwTradeLog.setProductName(productName);
    fwTradeLogService.save(fwTradeLog);
    log.info("[订单状态{}]=>{},当前商品id=>{},商品名称=>{}",fwTradeLog.getOrderId(), StatusEnum.TWO.getDesc(),fwTradeLog.getProductId(),fwTradeLog.getProductName());

    remoteSendServiceFeign.sendOrder(fwTradeLog);
    hashMap.put(TracingContext.tracing().groupId(), fwTradeLog.getId());
    int i=1/0;
}

重启订单服务
Postman输入localhost:9002/saveOrder
f15a6f74d633c63562e5c42743b75573_MD5.png

可以看到订单服务的日志如下，可以看到实际新增了一条记录，但是因为抛异常，被回滚掉了

2020-04-06 19:29:34.093  INFO 4513 --- [nio-9002-exec-2] c.y.t.t.o.service.impl.OrderServiceImpl  : [订单状态652702]=>待发货,当前商品id=>1586172574019,商品名称=>Mac pro 2020款
2020-04-06 19:29:34.696  INFO 4513 --- [-lcn-tcc-send-1] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-fw-transaction-lcn-tcc-send
2020-04-06 19:29:34.696  INFO 4513 --- [-lcn-tcc-send-1] c.netflix.loadbalancer.BaseLoadBalancer  : Client: fw-transaction-lcn-tcc-send instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=fw-transaction-lcn-tcc-send,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2020-04-06 19:29:34.705  INFO 4513 --- [-lcn-tcc-send-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2020-04-06 19:29:34.727  INFO 4513 --- [-lcn-tcc-send-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: fw-transaction-lcn-tcc-send.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2020-04-06 19:29:34.729  INFO 4513 --- [-lcn-tcc-send-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client fw-transaction-lcn-tcc-send initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=fw-transaction-lcn-tcc-send,current list of Servers=[192.168.0.102:9003],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:192.168.0.102:9003;	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@68e61e41
2020-04-06 19:29:35.058 ERROR 4513 --- [nio-9002-exec-2] c.c.txlcn.tc.core.DTXServiceExecutor     : business code error @group(8a815c4628537)
2020-04-06 19:29:35.098  INFO 4513 --- [nio-9002-exec-2] c.y.t.t.o.service.impl.OrderServiceImpl  : 当前产品Mac pro 2020款,事务执行失败，回滚tradeLogId为9的数据

发货服务的日志如下，因为上游系统发生异常回滚，所以发货服务已经发货的的记录也被回滚了

2020-04-06 19:29:35.014  INFO 4503 --- [nio-9003-exec-1] c.y.t.t.s.service.impl.SendServiceImpl   : [订单状态652702]=>待收货,当前商品id=>1586172574019,商品名称=>Mac pro 2020款
2020-04-06 19:29:35.078  INFO 4503 --- [c-rpc-service-0] c.y.t.t.s.service.impl.SendServiceImpl   : 当前产品Mac pro 2020款,事务执行失败，回滚tradeLogId为10的数据

数据库记录并没有，说明TxManager 进行了回滚
3edff946480bc4731a71e24e84a560ec_MD5.png