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本篇内容介绍了“SpringCloud Alibaba用Seata处理分布式事务的方法”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
在传统的单体项目中,我们使用@Transactional注解就能实现基本的ACID事务了。
但是前提是:
1) 数据库支持事务(如:MySQL的innoDB引擎)
2) 所有业务都在同一个数据库中执行
随着微服务架构的引入,需要对数据库进行分库分表,每个服务拥有自己的数据库,这样传统的事务就不起作用了,那么我们如何保证多个服务中数据的一致性呢?
这样就出现了分布式事务,而Seata就是为微服务架构而生的一种高性能、易于使用的分布式事务解决方案。
Seata 中有三个基础组件:
Transaction Coordinator(TC协调者):维护全局和分支事务的状态,驱动全局提交或回滚。
Transaction Manager(TM事务管理):定义全局事务的范围,开启、提交或回滚一个全局事务。
Resource Manager(RM资源管理):管理分支事务资源,与 TC 通讯并报告分支事务状态,管理本地事务的提交与回滚。
可以这么说一个分布式事务就是全局事务GlobalTransaction,而全局事务是由一个个的分支事务组成的,每个分支事务就是一个本地事务。
Seata的生命周期
TM 要求 TC 生成一个全局事务,并由 TC 生成一个全局事务XID 返回。
XID 通过微服务调用链传播。
RM 向 TC 注册本地事务,将其注册到 ID 为 XID 的全局事务中。
TM 要求 TC 提交或回滚XID 对应的全局事务。
TC 驱动 XID 对应的全局事务对应的所有的分支事务提交或回滚。
安装nacos,本案例使用了nacos作为注册中心
https://github.com/alibaba/nacos/releases
下载nacos,本文使用的是windows版本1.4.0
使用命令行进入bin目录,以单机模式启动nacos
startup -m standalone
安装和配置Seata
http://seata.io/zh-cn/blog/download.html
下载Seata,这里是Windows版本的1.4.0
解压后,进入conf目录,配置file.conf和registry.conf两个文件
file.conf主要是数据库的配置,配置如下
registry.conf 是注册中心的配置
另外conf目录中还需要一个脚本文件:nacos-config.sh 用于对nacos进行初始化配置
在seata1.4.0中是没有的,需要自行创建,内容如下:
#!/usr/bin/env bash # Copyright 1999-2019 Seata.io Group. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at、 # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. while getopts ":h:p:g:t:u:w:" opt do case $opt in h) host=$OPTARG ;; p) port=$OPTARG ;; g) group=$OPTARG ;; t) tenant=$OPTARG ;; u) username=$OPTARG ;; w) password=$OPTARG ;; ?) echo " USAGE OPTION: $0 [-h host] [-p port] [-g group] [-t tenant] [-u username] [-w password] " exit 1 ;; esac done urlencode() { for ((i=0; i < ${#1}; i++)) do char="${1:$i:1}" case $char in [a-zA-Z0-9.~_-]) printf $char ;; *) printf '%%%02X' "'$char" ;; esac done } if [[ -z ${host} ]]; then host=localhost fi if [[ -z ${port} ]]; then port=8848 fi if [[ -z ${group} ]]; then group="SEATA_GROUP" fi if [[ -z ${tenant} ]]; then tenant="" fi if [[ -z ${username} ]]; then username="" fi if [[ -z ${password} ]]; then password="" fi nacosAddr=$host:$port contentType="content-type:application/json;charset=UTF-8" echo "set nacosAddr=$nacosAddr" echo "set group=$group" failCount=0 tempLog=$(mktemp -u) function addConfig() { curl -X POST -H "${contentType}" "http://$nacosAddr/nacos/v1/cs/configs?dataId=$(urlencode $1)&group=$group&content=$(urlencode $2)&tenant=$tenant&username=$username&password=$password" >"${tempLog}" 2>/dev/null if [[ -z $(cat "${tempLog}") ]]; then echo " Please check the cluster status. " exit 1 fi if [[ $(cat "${tempLog}") =~ "true" ]]; then echo "Set $1=$2 successfully " else echo "Set $1=$2 failure " (( failCount++ )) fi } count=0 for line in $(cat $(dirname "$PWD")/config.txt | sed s/[[:space:]]//g); do (( count++ )) key=${line%%=*} value=${line#*=} addConfig "${key}" "${value}" done echo "=========================================================================" echo " Complete initialization parameters, total-count:$count , failure-count:$failCount " echo "=========================================================================" if [[ ${failCount} -eq 0 ]]; then echo " Init nacos config finished, please start seata-server. " else echo " init nacos config fail. " fi
在seata的根目录,与conf同级的目录下,还需要config.txt 配置文件,默认也是没有的
只需要对mysql的配置进行修改
完整文件:
transport.type=TCP transport.server=NIO transport.heartbeat=true transport.enableClientBatchSendRequest=true transport.threadFactory.bossThreadPrefix=NettyBoss transport.threadFactory.workerThreadPrefix=NettyServerNIOWorker transport.threadFactory.serverExecutorThreadPrefix=NettyServerBizHandler transport.threadFactory.shareBossWorker=false transport.threadFactory.clientSelectorThreadPrefix=NettyClientSelector transport.threadFactory.clientSelectorThreadSize=1 transport.threadFactory.clientWorkerThreadPrefix=NettyClientWorkerThread transport.threadFactory.bossThreadSize=1 transport.threadFactory.workerThreadSize=default transport.shutdown.wait=3 service.vgroupMapping.my_test_tx_group=default service.default.grouplist=127.0.0.1:8091 service.enableDegrade=false service.disableGlobalTransaction=false client.rm.asyncCommitBufferLimit=10000 client.rm.lock.retryInterval=10 client.rm.lock.retryTimes=30 client.rm.lock.retryPolicyBranchRollbackOnConflict=true client.rm.reportRetryCount=5 client.rm.tableMetaCheckEnable=false client.rm.tableMetaCheckerInterval=60000 client.rm.sqlParserType=druid client.rm.reportSuccessEnable=false client.rm.sagaBranchRegisterEnable=false client.rm.tccActionInterceptorOrder=-2147482648 client.tm.commitRetryCount=5 client.tm.rollbackRetryCount=5 client.tm.defaultGlobalTransactionTimeout=60000 client.tm.degradeCheck=false client.tm.degradeCheckAllowTimes=10 client.tm.degradeCheckPeriod=2000 client.tm.interceptorOrder=-2147482648 store.mode=file store.lock.mode=file store.session.mode=file store.publicKey=xx store.file.dir=file_store/data store.file.maxBranchSessionSize=16384 store.file.maxGlobalSessionSize=512 store.file.fileWriteBufferCacheSize=16384 store.file.flushDiskMode=async store.file.sessionReloadReadSize=100 store.db.datasource=druid store.db.dbType=mysql store.db.driverClassName=com.mysql.jdbc.Driver store.db.url=jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&rewriteBatchedStatements=true store.db.user=root store.db.password=123456 store.db.minConn=5 store.db.maxConn=30 store.db.globalTable=global_table store.db.branchTable=branch_table store.db.queryLimit=100 store.db.lockTable=lock_table store.db.maxWait=5000 store.redis.mode=single store.redis.single.host=127.0.0.1 store.redis.single.port=6379 store.redis.sentinel.masterName=xx store.redis.sentinel.sentinelHosts=xx store.redis.maxConn=10 store.redis.minConn=1 store.redis.maxTotal=100 store.redis.database=0 store.redis.password=xx store.redis.queryLimit=100 server.recovery.committingRetryPeriod=1000 server.recovery.asynCommittingRetryPeriod=1000 server.recovery.rollbackingRetryPeriod=1000 server.recovery.timeoutRetryPeriod=1000 server.maxCommitRetryTimeout=-1 server.maxRollbackRetryTimeout=-1 server.rollbackRetryTimeoutUnlockEnable=false server.distributedLockExpireTime=10000 client.undo.dataValidation=true client.undo.logSerialization=jackson client.undo.onlyCareUpdateColumns=true server.undo.logSaveDays=7 server.undo.logDeletePeriod=86400000 client.undo.logTable=undo_log client.undo.compress.enable=true client.undo.compress.type=zip client.undo.compress.threshold=64k log.exceptionRate=100 transport.serialization=seata transport.compressor=none metrics.enabled=false metrics.registryType=compact metrics.exporterList=prometheus metrics.exporterPrometheusPort=9898
在conf目录中,使用Git Bash进入命令行,输入
sh nacos-config.sh 127.0.0.1
这是对Seata进行初始化配置,上图表示所有配置都成功设置了
在nacos中可以看到出现了seata相关的配置
接下来在seata数据库中,新建三个表
drop table if exists `global_table`; create table `global_table` ( `xid` varchar(128) not null, `transaction_id` bigint, `status` tinyint not null, `application_id` varchar(32), `transaction_service_group` varchar(32), `transaction_name` varchar(128), `timeout` int, `begin_time` bigint, `application_data` varchar(2000), `gmt_create` datetime, `gmt_modified` datetime, primary key (`xid`), key `idx_gmt_modified_status` (`gmt_modified`, `status`), key `idx_transaction_id` (`transaction_id`) ); drop table if exists `branch_table`; create table `branch_table` ( `branch_id` bigint not null, `xid` varchar(128) not null, `transaction_id` bigint , `resource_group_id` varchar(32), `resource_id` varchar(256) , `lock_key` varchar(128) , `branch_type` varchar(8) , `status` tinyint, `client_id` varchar(64), `application_data` varchar(2000), `gmt_create` datetime, `gmt_modified` datetime, primary key (`branch_id`), key `idx_xid` (`xid`) ); drop table if exists `lock_table`; create table `lock_table` ( `row_key` varchar(128) not null, `xid` varchar(96), `transaction_id` long , `branch_id` long, `resource_id` varchar(256) , `table_name` varchar(32) , `pk` varchar(36) , `gmt_create` datetime , `gmt_modified` datetime, primary key(`row_key`) );
在项目相关的数据库中,新建表undo_log 用于记录撤销日志
CREATE TABLE `undo_log` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `branch_id` bigint(20) NOT NULL, `xid` varchar(100) NOT NULL, `context` varchar(128) NOT NULL, `rollback_info` longblob NOT NULL, `log_status` int(11) NOT NULL, `log_created` datetime NOT NULL, `log_modified` datetime NOT NULL, `ext` varchar(100) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
最后在bin目录中,启动命令行,执行seata-server.bat 启动Seata服务
项目应用Seata
SpringCloud项目中有两个服务:订单服务和库存服务,基本业务是:
购买商品
插入订单
减少库存
订单详情表
DROP TABLE IF EXISTS `tb_order_detail`; CREATE TABLE `tb_order_detail` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '订单详情id ', `order_id` bigint(20) NOT NULL COMMENT '订单id', `sku_id` bigint(20) NOT NULL COMMENT 'sku商品id', `num` int(11) NOT NULL COMMENT '购买数量', `title` varchar(256) NOT NULL COMMENT '商品标题', `own_spec` varchar(1024) DEFAULT '' COMMENT '商品动态属性键值集', `price` bigint(20) NOT NULL COMMENT '价格,单位:分', `image` varchar(128) DEFAULT '' COMMENT '商品图片', PRIMARY KEY (`id`), KEY `key_order_id` (`order_id`) USING BTREE ) ENGINE=MyISAM AUTO_INCREMENT=131 DEFAULT CHARSET=utf8 COMMENT='订单详情表';
库存表
DROP TABLE IF EXISTS `tb_stock`; CREATE TABLE `tb_stock` ( `sku_id` bigint(20) NOT NULL COMMENT '库存对应的商品sku id', `seckill_stock` int(9) DEFAULT '0' COMMENT '可秒杀库存', `seckill_total` int(9) DEFAULT '0' COMMENT '秒杀总数量', `stock` int(9) NOT NULL COMMENT '库存数量', PRIMARY KEY (`sku_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='库存表,代表库存,秒杀库存等信息';
父项目定义了springboot、springcloud、springcloud-alibaba的版本
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.10.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-alibaba-dependencies</artifactId> <version>0.9.0.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-alibaba-dependencies</artifactId> <version>2.2.1.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Hoxton.SR8</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>
子项目的依赖定义了nacos和seata客户端
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.3.2</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-seata</artifactId> <exclusions> <exclusion> <groupId>io.seata</groupId> <artifactId>seata-spring-boot-starter</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>io.seata</groupId> <artifactId>seata-spring-boot-starter</artifactId> <version>1.2.0</version> </dependency>
子项目配置文件
完整配置
server: port: 8001 spring: application: name: stock-service cloud: nacos: discovery: server-addr: localhost:8848 alibaba: seata: enabled: true enable-auto-data-source-proxy: true tx-service-group: my_test_tx_group registry: type: nacos nacos: application: seata-server server-addr: 127.0.0.1:8848 username: nacos password: nacos config: type: nacos nacos: server-addr: 127.0.0.1:8848 group: SEATA_GROUP username: nacos password: nacos service: vgroup-mapping: my_test_tx_group: default disable-global-transaction: false client: rm: report-success-enable: false datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/eshop?serverTimezone=UTC&useUnicode=true&useSSL=false&characterEncoding=utf8 username: root password: 123456
库存服务定义了减库存的方法
@RestController public class StockController { @Autowired private IStockService stockService; @PutMapping("/stock") public ResponseEntity<Stock> reduceSkuStock(@RequestParam("skuId")Long skuId, @RequestParam("number")Integer number){ Stock stock = stockService.getById(skuId); if(stock.getStock() < number){ throw new RuntimeException("库存不足,SkuId:" + skuId); } stock.setStock(stock.getStock() - number); stockService.updateById(stock); return ResponseEntity.ok(stock); } }
订单服务在插入订单后,使用Feign调用了减库存的服务
@Service public class OrderDetailServiceImpl extends ServiceImpl<OrderDetailMapper, OrderDetail> implements IOrderDetailService { //库存服务Feign @Autowired private StockFeignClient stockFeignClient; // @Transactional @GlobalTransactional(rollbackFor = {Exception.class}) @Override public void makeOrder(OrderDetail orderDetail) { this.save(orderDetail); //保存订单 int x = 11 / 0; //抛出异常 //减库存 stockFeignClient.reduceSkuStock(orderDetail.getSkuId(),orderDetail.getNum()); } }
插订单和减库存属于两个服务,传统的@Transactional已经不能保证它们的原子性了
这里使用了Seata提供的@GlobalTransactional全局事务注解,出现任何异常后都能实现业务回滚。
测试用例:
@RunWith(SpringRunner.class) @SpringBootTest public class OrderServiceApplicationTests { @Autowired private IOrderDetailService orderDetailService; @Test public void testOrder() { OrderDetail orderDetail = new OrderDetail(); orderDetail.setNum(100); orderDetail.setOrderId(9999L); orderDetail.setPrice(9999L); orderDetail.setSkuId(27359021728L); orderDetail.setTitle(UUID.randomUUID().toString()); orderDetailService.makeOrder(orderDetail); } }
运行后看到启动了全局事务,发生异常后,两个服务也都能成功回滚。
“SpringCloud Alibaba用Seata处理分布式事务的方法”的内容就介绍到这里了,感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站,小编将为大家输出更多高质量的实用文章!
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