背景
在前面的文章中，我们已经讲解了如何搭建Seata server1.5.2版本，接下来我们要使用搭建好的Seata server来真正集成分布式事务到我们的spring cloud项目当中。
我们在接下来的项目中，将以电商网站下单功能作为示例来讲述如何集成Seata AT模式。
1.用户下单请求进入Business业务入口，也就是我们的TM，TM立马与TC请求开启全局事务，拿到XID；
2.TM拿到XID后，依次通过RPC并携带XID去调用
钱包扣款、创建订单；
- 在接收到远程调用时，RM获取XID，并执行业务逻辑（对应扣款、创建订单），同时生成undo_log（seata的undo_log）记录，此时分支事务还未提交，此刻RM向TC注册分支事务，并产生行锁，注册成功后，将提交分支事务；后续如果需要回滚，将根据undo_log回滚；
3.创建订单的过程中，又需要通过RPC调用实现
扣减库存的操作；操作流程与第2步一样；4.在所有服务都调用完毕正常返回后，TM发起全局事务提交动作；或者在其中任意服务调用失败后TM发起全局事务回滚动作；
5.TC收到全局事务提交或回滚请求后，依次通知所有分支事务提交或回滚，以便达到分布式事务提交或回滚的目的；
注意：在seata中，是允许TM和RM放在一个服务当中的，当前示例把TM和RM拆开来演示能够更加清晰地阐述TM和RM各自的功能，真实开发或生产环境中，开发人员可灵活使用。
项目结构
1.awesome-business是整个项目的入口，该服务与前端直接交互，为前端提供服务接口；
2.
awesome-account是钱包功能所在的服务，包含钱包扣款功能；3.
awesome-order包含创建订单的功能；4.
awesome-storage包含扣减库存的功能；5.
account-api、order-api、storage-api的作用是暴露接口给awesome-business使用，做一个接口桥接的作用。
依赖
awesome-business作为TM，并同时对前端提供API，需要的功能包括spring mvc、服务发现、RPC调用、seata分布式事务等，所以对应的依赖如下：
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.7.3</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <artifactId>awesome-business</artifactId> <version>0.0.1-SNAPSHOT</version> <name>awesome-business</name> <description>awesome-business</description> <properties> <java.version>11</java.version> <spring-cloud.version>2021.0.4</spring-cloud.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <!-- spring mvc功能--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <!-- 服务发现--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> <version>2021.0.4.0</version> </dependency> <!-- RPC调用工具--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> <version>3.1.4</version> </dependency> <!-- 替换默认的URLConnection，改为okhttp，并添加链接池--> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-okhttp</artifactId> <version>11.9.1</version> </dependency> <!-- openFeign负载均衡由ribbon改为loadbalancer--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-loadbalancer</artifactId> <version>3.1.4</version> </dependency> <!-- 解决项目启动警告：LoadBalancerCacheManager not available, returning delegate without caching.--> <!-- 如果注册中心有自己的缓存，那么就可以禁用loadbalancer的缓存--> <dependency> <groupId>com.github.ben-manes.caffeine</groupId> <artifactId>caffeine</artifactId> <version>3.1.1</version> </dependency> <!-- 解决项目启动警告：Spring Cloud LoadBalancer is currently working with the default cache. You can switch to using Caffeine cache, by adding it and org.springframework.cache.caffeine.CaffeineCacheManager to the classpath.--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> </dependency> <!-- 分布式事务框架Seata --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-seata</artifactId> <version>2021.0.4.0</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.12.0</version> </dependency> <!-- account服务暴露接口--> <dependency> <groupId>com.example</groupId> <artifactId>account-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <!-- order服务暴露接口--> <dependency> <groupId>com.example</groupId> <artifactId>order-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <excludes> <exclude> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </exclude> </excludes> </configuration> </plugin> </plugins> </build> </project> 复制代码
awesome-account、awesome-order、awesome-storage作为RM，同时向awesome-business暴露接口，需要数据库操作、spring mvc、seata分布式事务等功能，可能也需要RPC调用，所以对应的依赖如下：
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.7.3</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <!-- 记得替换artifactId --> <artifactId>awesome-order</artifactId> <version>0.0.1-SNAPSHOT</version> <name>awesome-order</name> <description>awesome-order</description> <properties> <java.version>11</java.version> <spring-cloud.version>2021.0.4</spring-cloud.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- spring mvc功能 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <!--nacos注册中心--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> <version>2021.0.4.0</version> </dependency> <!-- RPC调用工具 --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> <version>3.1.4</version> </dependency> <!-- 替换默认的URLConnection，改为okhttp，并添加链接池--> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-okhttp</artifactId> <version>11.9.1</version> </dependency> <!-- openFeign负载均衡由ribbon改为loadbalancer--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-loadbalancer</artifactId> <version>3.1.4</version> </dependency> <!-- 解决项目启动警告：LoadBalancerCacheManager not available, returning delegate without caching.--> <!-- 如果注册中心有自己的缓存，那么就可以禁用loadbalancer的缓存--> <dependency> <groupId>com.github.ben-manes.caffeine</groupId> <artifactId>caffeine</artifactId> <version>3.1.1</version> </dependency> <!-- 解决项目启动警告：Spring Cloud LoadBalancer is currently working with the default cache. You can switch to using Caffeine cache, by adding it and org.springframework.cache.caffeine.CaffeineCacheManager to the classpath.--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> </dependency> <!--seata分布式事务框架--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-seata</artifactId> <version>2021.0.4.0</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <!-- 【数据库】mysql driver --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.30</version> </dependency> <!--【数据库】数据库连接池--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.2.11</version> </dependency> <!--【数据库】持久层框架 mybatis--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.2.2</version> </dependency> <!--【数据库】分页插件--> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.4.3</version> </dependency> <!-- order服务自己的接口 --> <dependency> <groupId>com.example</groupId> <artifactId>order-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <!-- storage服务暴露的接口 --> <dependency> <groupId>com.example</groupId> <artifactId>storage-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> <build> <resources> <resource> <directory>src/main/resources</directory> <includes> <include>**/*.properties</include> <include>**/*.yml</include> <include>**/*.xml</include> </includes> <filtering>true</filtering> </resource> </resources> <plugins> <!-- mybatis-generator maven插件，用于生成DAO代码 --> <plugin> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-maven-plugin</artifactId> <version>1.4.1</version> <configuration> <verbose>true</verbose> <overwrite>true</overwrite> <!-- mybatis-generator配置文件路径 --> <configurationFile>${basedir}/src/main/resources/mybatis/generator/generatorConfig.xml </configurationFile> </configuration> </plugin> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <excludes> <exclude> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </exclude> </excludes> </configuration> </plugin> </plugins> </build> </project> 复制代码
以上是awesome-order服务对应的依赖，awesome-account、awesome-storage可参照上面的依赖按需修改，awesome-account、awesome-storage因为不需要RPC调用，可删除对应的RPC调用依赖及其相关的优化关联的依赖，也就是以下这一段：
<!-- RPC调用工具 --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> <version>3.1.4</version> </dependency> <!-- 替换默认的URLConnection，改为okhttp，并添加链接池--> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-okhttp</artifactId> <version>11.9.1</version> </dependency> <!-- openFeign负载均衡由ribbon改为loadbalancer--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-loadbalancer</artifactId> <version>3.1.4</version> </dependency> <!-- 解决项目启动警告：LoadBalancerCacheManager not available, returning delegate without caching.--> <!-- 如果注册中心有自己的缓存，那么就可以禁用loadbalancer的缓存--> <dependency> <groupId>com.github.ben-manes.caffeine</groupId> <artifactId>caffeine</artifactId> <version>3.1.1</version> </dependency> <!-- 解决项目启动警告：Spring Cloud LoadBalancer is currently working with the default cache. You can switch to using Caffeine cache, by adding it and org.springframework.cache.caffeine.CaffeineCacheManager to the classpath.--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> </dependency>
