分布式事务的学习
解决分布式事务的理论方案#
- 全局事务XA规范
- 最终一致性：2PC，TCC
- 可靠消息服务（例如rocketmq的事务消息；rabbitmq基于ack的消息确认）
- 最大努力通知
分布式事务场景有如下几种形式：
- 一个应用中操作多个数据库需要保证数据一致性
- 微服务不同模块操作同一个数据库需要保证数据一致性
- 微服务不同模块操作不同数据库需要保证数据一致性
理论落地实现技术-Atomikos#
Atomikos是基于XA规范的Java实现版本JTA进行开发的一项技术，这项技术也比较成熟了。针对mysql数据库Atomikos只有在InnoDB存储引擎下才有效，针对MyISAM就无法控制事务了，开发的时候需要注意这点
XA是强一致性事务，性能不佳，互联网项目中中的应该不多，因此Atomikos更适合在一个单体应用中对多个数据源进行分布式事务
使用Atomikos开发，必须将不同数据源的mapper进行分包管理，也即不同数据源的Dao层放在不同的包下，这样mybatis的mapperScan扫描不同包下就可以获得正确的连接，建议将mapper的xml映射，实体类也进行分包管理
Atomikos和Spring整合#
1.引入依赖#
<dependency>
<groupId>javax.transaction</groupId>
<artifactId>jta</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>atomikos-util</artifactId>
<version>4.0.6</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions</artifactId>
<version>4.0.6</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions-api</artifactId>
<version>4.0.6</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions-jdbc</artifactId>
<version>4.0.6</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions-jta</artifactId>
<version>4.0.6</version>
</dependency>
2.多个数据源连接信息配置#
# 数据源1
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql:///ssm_crud?useSSl=false&characterEncoding=utf-8
jdbc.user=root
jdbc.password=root
# 数据源2
jdbc.shop.driverClass=com.mysql.jdbc.Driver
jdbc.shop.jdbcUrl=jdbc:mysql:///shop?useSSl=false&characterEncoding=utf-8
jdbc.shop.user=root
jdbc.shop.password=root
3.在spring的application.properties文件中配置如下内容#
- 配置dataSource，这里需要使用AtomikosDataSourceBean
<!-- 引入jdbc.properties文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!--这里配置一个抽象的bean 将数据源一些共有配置抽取出来，不是必须这样配置，只是为了抽出共有配置-->
<bean id="abstractXADataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init" destroy-method="close" abstract="true">
<property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>
<property name="maxPoolSize" value="30"/>
<property name="minPoolSize" value="10"/>
<property name="borrowConnectionTimeout" value="60"/>
<property name="reapTimeout" value="20"/>
<property name="maxIdleTime" value="60"/>
<property name="maintenanceInterval" value="60"/>
</bean>
<!--数据库1基本配置-->
<bean id="dataSourceOne" parent="abstractXADataSource">
<property name="uniqueResourceName" value="dataSourceOne"/>
<!--数据库驱动-->
<property name="xaProperties">
<props>
<prop key="url">${jdbc.jdbcUrl}</prop>
<prop key="user">${jdbc.user}</prop>
<prop key="password">${jdbc.password}</prop>
</props>
</property>
</bean>
<!--数据库2基本配置-->
<bean id="dataSourceTwo" parent="abstractXADataSource">
<property name="uniqueResourceName" value="dataSourceTwo"/>
<!--数据库驱动-->
<property name="xaProperties">
<props>
<prop key="url">${jdbc.shop.jdbcUrl}</prop>
<prop key="user">${jdbc.shop.user}</prop>
<prop key="password">${jdbc.shop.password}</prop>
</props>
</property>
</bean>
- 配置sqlSessionFactory (mapperLocations，typeAliasesPackage也可以配置不同的路径)
<!--有几个数据源就需要配置几个sqlSessionFactory-->
<bean id="sqlSessionFactoryOne" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="configLocation" value="classpath:mybatis/sqlMapConfig.xml"></property>
<property name="dataSource" ref="dataSourceOne"></property>
<!-- 指定mybatis，mapper文件的位置 -->
<property name="mapperLocations" value="classpath:mapper/*.xml"></property>
<!-- 配置实体类别名 -->
<property name="typeAliasesPackage" value="cn.lynu.model"></property>
</bean>
<bean id="sqlSessionFactoryTwo" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="configLocation" value="classpath:mybatis/sqlMapConfig.xml"></property>
<property name="dataSource" ref="dataSourceTwo"></property>
<!-- 指定mybatis，mapper文件的位置 -->
<property name="mapperLocations" value="classpath:mapper/*.xml"></property>
<!-- 配置实体类别名 -->
<property name="typeAliasesPackage" value="cn.lynu.model"></property>
</bean>
- 配置mapper扫描器（注意这里basePackage扫描的路径）
<!--有几个数据源就需要配置几个mapper扫描器-->
<bean id="mapperScannerConfigurerOne" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="cn.lynu.mapper"></property>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryOne"></property>
</bean>
<bean id="mapperScannerConfigurerTwo" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="cn.lynu.shopmapper"></property>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactoryTwo"></property>
</bean>
- 配置事务管理
<!--配置atomikos事务管理器-->
<bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager" init-method="init" destroy-method="close">
<property name="forceShutdown" value="false"/>
</bean>
<!--配置atomikos事务-->
<bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
<property name="transactionTimeout" value="300"/>
</bean>
<!--配置spring与jta事务整合-->
<bean id="springTransactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">
<property name="transactionManager" ref="atomikosTransactionManager"/>
<property name="userTransaction" ref="atomikosUserTransaction"/>
<property name="allowCustomIsolationLevels" value="true"/>
</bean>
- 配置事务切面，这里使用的是切面的方式配置事务，实际上使用注解配置也可以
<!-- 配置通知 -->
<tx:advice id="txAdvice" transaction-manager="springTransactionManager">
<tx:attributes>
<!-- 匹配业务类中的方法 -->
<tx:method name="save*" propagation="REQUIRED"/>
<tx:method name="insert*" propagation="REQUIRED"/>
<tx:method name="update*" propagation="REQUIRED"/>
<tx:method name="delete*" propagation="REQUIRED"/>
<tx:method name="find*" propagation="SUPPORTS" read-only="true"/>
<tx:method name="select*" propagation="SUPPORTS" read-only="true"/>
<tx:method name="get*" propagation="SUPPORTS" read-only="true"/>
</tx:attributes>
</tx:advice>
<!-- 配置aop -->
<aop:config>
<!-- 配置切点 -->
<aop:pointcut expression="execution(* cn.lynu.service.*.*(..))" id="cut"/>
<!-- 配置切面 -->
<aop:advisor advice-ref="txAdvice" pointcut-ref="cut"/>
</aop:config>
如果是注解方式就如下配置：
<tx:annotation-driven transaction-manager="springTransactionManager"/>
重点就是这里的transaction-manager
接下来就可以进行测试了：
package cn.lynu.service;
import cn.lynu.mapper.EmployeeMapper;
import cn.lynu.model.Employee;
import cn.lynu.model.ShopProduct;
import cn.lynu.shopmapper.ShopProductMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.math.BigDecimal;
@Service
public class AtomikosService {
@Autowired
private EmployeeMapper employeeMapper;
@Autowired
private ShopProductMapper shopProductMapper;
public void saveMethod() {
ShopProduct product = new ShopProduct();
product.setPname("测试1");
product.setPprice(new BigDecimal("100"));
product.setStock(100);
shopProductMapper.insertProduct(product);
Employee employee = new Employee();
employee.setEmpName("测试1");
employee.setEmpSex("1");
employee.setEmpEmail("123@qq.com");
employee.setdId(1);
employeeMapper.insertSelective(employee);
int i = 1 / 0;
}
}
查看运行日志，出现如下内容就表示分布式事务正常回滚
Atomikos和SpringBoot整合#
这里我用的是Mybatis-Plus，Mybatis配置方法也类似，可以参考：springboot jta atomikos实现分布式事物管理
1.引入依赖#
<!--使用atomikos实现分布式事务-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jta-atomikos</artifactId>
</dependency>
2.修改SpringBoot配置文件#
spring:
# 数据源配置
datasource:
databases1:
# type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql:///ssm_crud?useSSl=false&characterEncoding=utf-8
username: root
password: root
databases2:
# type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql:///shop?useSSl=false&characterEncoding=utf-8
username: root
password: root
mybatis-plus:
#Mapper扫描在MyBatisPlusConfigDS.java配置类中进行了配置
#实体扫描，多个package用逗号或者分号分隔
typeAliasesPackage: com.ds.entity
global-config:
db-config:
#主键类型 AUTO:"数据库ID自增", INPUT:"用户输入ID", ID_WORKER:"全局唯一ID (默认,数字类型唯一ID)", UUID:"全局唯一ID UUID";
id-type: AUTO
#字段策略 IGNORED:"忽略判断", NOT_NULL:"非 NULL 判断"), NOT_EMPTY:"非空判断"
field-strategy: NOT_NULL
#是否开启大写命名，默认false不开启
#capital-mode: true
configuration:
#配置返回数据库(column下划线命名&&返回java实体是驼峰命名)，自动匹配无需as（没开启这个，SQL需要写as： select user_id as userId）
map-underscore-to-camel-case: true
cache-enabled: false
#配置JdbcTypeForNull, oracle数据库必须配置
jdbc-type-for-null: 'null'
#打印sql日志
# log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
3.Mybatis-Plus配置类#
因为有两个数据源需要控制分布式事务，所以就需要写两个配置类，并且将basePackages扫描不同包下的mapper，这里也需要对不同数据源的Dao层进行分包，也建议将mapper的xml映射，实体类也进行分包管理
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PerformanceInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.mysql.jdbc.jdbc2.optional.MysqlXADataSource;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import javax.sql.DataSource;
@Configuration
// 扫描的Dao层 多个数据源对应的Mapper文件以及XML文件需要分开配置(放在不同的包下) 如果放在同一个文件夹会报错
@MapperScan(basePackages = "com.ds.mapper", sqlSessionTemplateRef = "ds1SqlSessionTemplate")
public class MyBatisPlusConfigDS1 {
/**
* 数据源1配置信息(url password username...)
*/
@Bean(name = "ds1DataSourceProperties")
@ConfigurationProperties(prefix = "spring.datasource.databases1")
public DataSourceProperties ds1DataSourceProperties() {
return new DataSourceProperties();
}
/**
* 配置数据源1
* @param config 数据源配置信息
* @return
*/
@Primary
@Bean(name = "ds1DataSource")
public DataSource ds1DataSource(@Qualifier("ds1DataSourceProperties") DataSourceProperties config) {
// 创建Mysql实现XA规范的分布式数据源
MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
// 设置连接信息
mysqlXaDataSource.setUrl(config.getUrl());
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
mysqlXaDataSource.setPassword(config.getPassword());
mysqlXaDataSource.setUser(config.getUsername());
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
// 数据源改为Atomikos，将事务交给Atomikos统一管理
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(mysqlXaDataSource);
// Druid对于XA的支持,将上面代码注释,打开以下注释
/*DruidXADataSource druidXADataSource = new DruidXADataSource();
druidXADataSource.setUrl(config.getUrl());
druidXADataSource.setPassword(config.getPassword());
druidXADataSource.setUsername(config.getUsername());
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(druidXADataSource);*/
xaDataSource.setUniqueResourceName("ds1DataSource");
// xaDataSource.setMinPoolSize(config.getMinPoolSize());
// xaDataSource.setMaxPoolSize(config.getMaxPoolSize());
// xaDataSource.setMaxLifetime(config.getMaxLifetime());
// xaDataSource.setBorrowConnectionTimeout(config.getBorrowConnectionTimeout());
// xaDataSource.setLoginTimeout(config.getLoginTimeout());
// xaDataSource.setMaintenanceInterval(config.getMaintenanceInterval());
// xaDataSource.setMaxIdleTime(config.getMaxIdleTime());
// xaDataSource.setTestQuery(config.getTestQuery());
return xaDataSource;
}
/**
* 配置数据源1的sqlSessionFactory
* 使用MybatisPlus的MybatisSqlSessionFactoryBean 替换Mybatis的SqlSessionFactoryBean
* @param dataSource 数据源
* @return
* @throws Exception
*/
@Bean(name = "ds1SqlSessionFactory")
public SqlSessionFactory ds1SqlSessionFactory(@Qualifier("ds1DataSource") DataSource dataSource)
throws Exception {
MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSource);
sqlSessionFactoryBean.setPlugins(new Interceptor[]{
new PaginationInterceptor(), // 分页插件
new PerformanceInterceptor().setFormat(true) // SQL格式化插件
});
// 配置为扫描数据源1所有的mapper
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/com/ds/mapper/*.xml"));
return sqlSessionFactoryBean.getObject();
}
/**
* 配置数据源1的SqlSessionTemplate
* @param sqlSessionFactory 数据源1的sqlSessionFactory
*/
@Bean(name = "ds1SqlSessionTemplate")
public SqlSessionTemplate ds1SqlSessionTemplate(@Qualifier("ds1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PerformanceInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.mysql.jdbc.jdbc2.optional.MysqlXADataSource;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import javax.sql.DataSource;
import java.sql.SQLException;
@Configuration
@MapperScan(basePackages = "com.ds.mapper2", sqlSessionTemplateRef = "ds2SqlSessionTemplate")
public class MyBatisPlusConfigDS2 {
@Bean(name = "ds2DataSourceProperties")
@ConfigurationProperties(prefix = "spring.datasource.databases2")
public DataSourceProperties ds1DataSourceProperties() {
return new DataSourceProperties();
}
// 配置数据源
@Bean(name = "ds2DataSource")
public DataSource ds2DataSource(@Qualifier("ds2DataSourceProperties") DataSourceProperties config) throws SQLException {
MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
mysqlXaDataSource.setUrl(config.getUrl());
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
mysqlXaDataSource.setPassword(config.getPassword());
mysqlXaDataSource.setUser(config.getUsername());
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(mysqlXaDataSource);
// Druid对于XA的支持,将上面代码注释,打开以下注释
/*DruidXADataSource druidXADataSource = new DruidXADataSource();
druidXADataSource.setUrl(config.getUrl());
druidXADataSource.setPassword(config.getPassword());
druidXADataSource.setUsername(config.getUsername());
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(druidXADataSource);*/
xaDataSource.setUniqueResourceName("ds2DataSource");
// xaDataSource.setMinPoolSize(config.getMinPoolSize());
// xaDataSource.setMaxPoolSize(config.getMaxPoolSize());
// xaDataSource.setMaxLifetime(config.getMaxLifetime());
// xaDataSource.setBorrowConnectionTimeout(config.getBorrowConnectionTimeout());
// xaDataSource.setLoginTimeout(config.getLoginTimeout());
// xaDataSource.setMaintenanceInterval(config.getMaintenanceInterval());
// xaDataSource.setMaxIdleTime(config.getMaxIdleTime());
// xaDataSource.setTestQuery(config.getTestQuery());
return xaDataSource;
}
@Bean(name = "ds2SqlSessionFactory")
public SqlSessionFactory ds2SqlSessionFactory(@Qualifier("ds2DataSource") DataSource dataSource)
throws Exception {
MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSource);
sqlSessionFactoryBean.setPlugins(new Interceptor[]{
new PaginationInterceptor(), // 分页插件
new PerformanceInterceptor().setFormat(true) // SQL格式化插件
});
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/com/ds/mapper2/*.xml"));
return sqlSessionFactoryBean.getObject();
}
@Bean(name = "ds2SqlSessionTemplate")
public SqlSessionTemplate ds2SqlSessionTemplate(
@Qualifier("ds2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
不同数据库连接池对Atomikos的支持#
默认的MysqlXADataSource是支持XA规范的；而我们常用的数据库连接池如：HikariCP，druid，dbcp，c3p0等貌似有些还未支持，具体情况如下图：
理论落地实现技术-Seata#
Seata是阿里开源的分布式，比较适合在分布式微服务项目中使用，如SpringCloud，Dubbo，官方也给出一些整合的案例
Seata中有TC，TM，RM的概念解释如下：
TC (Transaction Coordinator) - 事务协调者：维护全局和分支事务的状态，驱动全局事务提交或回滚。Seata提供实现好的seata-server作为TC。
TM (Transaction Manager) - 事务管理器：定义全局事务的范围：开始全局事务、提交或回滚全局事务。
RM (Resource Manager) - 资源管理器：管理分支事务处理的资源，与TC交谈以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚。RM更多表示的就是每一个数据源。
TC已经由Seata提供了，我们只需要将从下载地址后配置运行即可，在项目中配置还需要我们配置TC和RM，这两者通过jar包的方式引入项目
Seata和SpringCloud整合#
1.修改seata-server配置并运行#
主要修改的是conf目录下的registry.conf，file.conf这两个文件。registry.conf只要配置注册中心和配置中心，Seata的注册中心可以是file 、nacos 、eureka、redis、zk、consul、etcd3、sofa类型，而配置中心可以是file、nacos 、apollo、zk、consul、etcd3这几种类型，如果我们将配置中心使用file类型，那么就需要修改file.conf这个文件了。这里记录的就是用nacos作为Seata注册中心，file作为配置中心的方案，如果需要将配置中心也使用nacos就需要修改conf/nacos-config.txt，修改后运行conf/nacos-config.sh脚本，更详细可以参看[文档](nacos (seata.io))
这里我们使用的是Seata 0.9.0版本的 seata-server-0.9.0
registry.conf：
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
# 这里将注册中心type改为naccos
type = "nacos"
# 配置正确的naocs地址
nacos {
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = "0"
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
}
etcd3 {
cluster = "default"
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
application = "default"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
cluster = "default"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
# 使用file类型的配置中心
type = "file"
nacos {
serverAddr = "localhost"
namespace = ""
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
app.id = "seata-server"
apollo.meta = "http://192.168.1.204:8801"
}
zk {
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
etcd3 {
serverAddr = "http://localhost:2379"
}
# 因为使用了file类型的配置中心，所以接下来就需要修改file.conf文件
file {
name = "file.conf"
}
}
file.conf：
这里我们使用数据库持久化配置信息，并且vgroup_mapping.xxx配置的值很关键，值的内容无所谓但是之后我们会用到，这里配置的my_tx_group并没什么特殊意义
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#vgroup->rgroup 这里的值很关键，值的内容无所谓但是之后我们会用到，这里用的my_tx_group并没什么特殊意义
vgroup_mapping.my_test_tx_group = "my_tx_group"
#only support single node
default.grouplist = "localhost:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
tm.commit.retry.count = 1
tm.rollback.retry.count = 1
}
## transaction log store
store {
## store mode: file、db
# 使用数据库持久化配置信息
mode = "db"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
# 配置正确的数据库信息
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://localhost:3306/seata"
user = "root"
password = "root"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
local {
## store locks in user's database
}
remote {
## store locks in the seata's server
}
}
recovery {
#schedule committing retry period in milliseconds
committing-retry-period = 1000
#schedule asyn committing retry period in milliseconds
asyn-committing-retry-period = 1000
#schedule rollbacking retry period in milliseconds
rollbacking-retry-period = 1000
#schedule timeout retry period in milliseconds
timeout-retry-period = 1000
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
undo.log.save.days = 7
#schedule delete expired undo_log in milliseconds
undo.log.delete.period = 86400000
undo.log.table = "undo_log"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}
support {
## spring
spring {
# auto proxy the DataSource bean
datasource.autoproxy = false
}
}
因为需要在数据库持久化，所以就需要在数据库中提前生成表结构，建表语句在conf/db_store.sql，内容如下：
-- the table to store GlobalSession data
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`)
);
-- the table to store BranchSession data
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`)
);
-- the table to store lock data
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`)
);
当这两个配置文件修改完成之后运行bin/seata-server.sh/.bat就可以启动Seata-Server即可
2.在每一个涉及到分布式事务的项目中引入依赖#
因为spring-cloud-starter-alibaba-seata会自动引入Seata的依赖，但是自动引入的依赖版本可能不是我们需要的，就可以同故宫exclusion排除掉，这里我们用Seata 0.9.0版本
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>0.9.0</version>
</dependency>
3.修改对应项目中修改SpringBoot配置文件#
我们在SpringBoot的配置文将中添加如下配置：
spring:
cloud:
alibaba:
seata:
# 这里自定义的事务组名必须与seata-Server file.conf文件中配置的vgroup_mapping.xxx值一样
tx-service-group: my_tx_group
4.将registry.conf和file.conf文件放到对应项目的resources目录下#
实际上registry.conf和file.conf文件中多余的配置项可以删除，这里就放一个删除后的版本
registry.conf：
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "nacos"
nacos {
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
type = "file"
file {
name = "file.conf"
}
}
file.conf：这个file文件配置的vgroup_mapping.xxx就不与Seata Serve中的配置不同了，xxx必须是Seata Serve file.conf中配置的值，也就是my_tx_group
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
#vgroup->rgroup
vgroup_mapping.my_tx_group = "default"
#only support single node
default.grouplist = "127.0.0.1:8091"
#degrade current not support
enableDegrade = false
#disable
disable = false
#unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
tm.commit.retry.count = 1
tm.rollback.retry.count = 1
}
## transaction log store
store {
## store mode: file、db
mode = "db"
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://localhost:3306/seata"
user = "root"
password = "root"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
remote {
## store locks in the seata's server
}
}
recovery {
#schedule committing retry period in milliseconds
committing-retry-period = 1000
#schedule asyn committing retry period in milliseconds
asyn-committing-retry-period = 1000
#schedule rollbacking retry period in milliseconds
rollbacking-retry-period = 1000
#schedule timeout retry period in milliseconds
timeout-retry-period = 1000
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
undo.log.save.days = 7
#schedule delete expired undo_log in milliseconds
undo.log.delete.period = 86400000
undo.log.table = "undo_log"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}
support {
## spring
spring {
# auto proxy the DataSource bean
datasource.autoproxy = false
}
}
5.在对应项目中配置Seata提供的代理数据源#
package com.lynu.config;
import com.alibaba.druid.pool.DruidDataSource;
import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import javax.sql.DataSource;
/**
* 使用seata配置数据源DataSourceProxy以及mybatis的SqlSessionFactory
* 需要在启动类排除调用spring默认的mybatis的自动配置DataSourceAutoConfiguration
*/
@Configuration
public class DataSourceProxyConfig {
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource() {
return new DruidDataSource();
}
@Primary
@Bean("dataSource")
public DataSourceProxy dataSourceProxy(DataSource druidDataSource) {
return new DataSourceProxy(druidDataSource);
}
@Bean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSourceProxy);
SqlSessionFactory factory;
try {
factory = bean.getObject();
} catch (Exception e) {
throw new RuntimeException(e);
}
return factory;
}
}
因为使用的Mybatis操作数据库，所以配置的就是SqlSessionFactory，其他的持久层框架与之类似，接下来需要我们将SpringBoot自带的数据源自动配置排除掉，因为我们需要使用自己的配置，在SpringBoot启动类上：
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
6.在每一个涉及到分布式事务的数据库中添加undo_log表#
undo_log表结构在conf/db_undo_log.sql
drop table `undo_log`;
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;
接下来我们在需要开启分布式事务的Service方法上添加@GlobalTransactional注解即可
理论落地实现技术-TX-LCN#
TX-LCN比较适合在分布式微服务项目中使用，如SpringCloud，Dubbo
TX-LCN 主要有两个模块，Tx-Client(TC) Tx-Manager(TM). TC作为微服务下的依赖，TM是独立的服务，这里的TM，TC与Seata中的概念有些相反
版本说明：该框架作者正在开发6.0版本，而本次记录的是以5.0.2版本为准，TM下载地址
TX-LCN和SpringCloud整合#
1.启动TM服务#
TX-LCN的TM需要依赖MySQL+Redis，所以在下载目录txlcn-tm/src/main/resources/tx-manager.sql有建库建表语句
CREATE DATABASE IF NOT EXISTS `tx-manager` DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
USE `tx-manager`;
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
DROP TABLE IF EXISTS `t_tx_exception`;
CREATE TABLE `t_tx_exception` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`group_id` varchar(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
`unit_id` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
`mod_id` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
`transaction_state` tinyint(4) NULL DEFAULT NULL,
`registrar` tinyint(4) NULL DEFAULT NULL,
`ex_state` tinyint(4) NULL DEFAULT NULL COMMENT '0 待处理 1已处理',
`remark` varchar(10240) NULL DEFAULT NULL COMMENT '备注',
`create_time` datetime(0) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 967 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;
修改配置信息(txlcn-tm/src/main/resources/application.properties)
spring.application.name=TransactionManager
server.port=7970
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/tx-manager?characterEncoding=UTF-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto=update
spring.redis.host=127.0.0.1
spring.redis.port=6379
修改pom.xml文件配置的plugins，注释掉配置的插件，添加SpringBoot-Maven插件
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<fork>true</fork>
<addResources>true</addResources>
</configuration>
</plugin>
</plugins>
</build>
修改完这些文件之后就可以通过Maven构建了
mvn clean package -Dmaven.test.skip=true
java -jar target/txlcn-tm-5.0.2.RELEASE.jar
2.在每一个涉及到分布式事务的项目中引入依赖#
<dependency>
<groupId>com.codingapi.txlcn</groupId>
<artifactId>txlcn-tc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>com.codingapi.txlcn</groupId>
<artifactId>txlcn-txmsg-netty</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
3.在对应项目开启分布式事务注解#
在每一个涉及到分布式事务的微服务主类上使用@EnableDistributedTransaction
@SpringBootApplication
@EnableDistributedTransaction
public class DemoAApplication {
public static void main(String[] args) {
SpringApplication.run(DemoDubboClientApplication.class, args);
}
}
接下来再在每一个涉及到分布式事务的业务方法配置@LcnTransaction，注意这里不同于Seata，只要涉及到分布式事务的每一个微服务中的业务方法上都需要添加@LcnTransaction注解。添加注解之后分布式事务就生效了
TX-LCN的默认TM的本机默认端口：127.0.0.1:8070，如果需要修改就在SpringBoot配置文件中修改：
tx-lcn:
client:
manager-address: 127.0.0.1:8070
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