由于平时项目里有用到多个数据源，之前采用AOP的方式切换数据源，却发现事务无法生效。今天尝试了下在Spring Boot下创建多个数据源，并实现分布式事务，即多事务同步提交与回滚。
这里需要用到Atomikos，它是一种无需服务器支持的分布式事务组件。
接下来介绍如何搭建多数据源与分布式事务：
- pom.xml新增依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jta-atomikos</artifactId>
</dependency>
- application.properties新增多数据源配置
#开启JTA支持
spring.jta.enabled=true
#数据源def
spring.datasource.def.xa-properties.url=jdbc:mysql://localhost:3306/yysoft?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&rewriteBatchedStatements=true
spring.datasource.def.xa-properties.username=root
spring.datasource.def.xa-properties.password=mysql
spring.datasource.def.xa-data-source-class-name=com.alibaba.druid.pool.xa.DruidXADataSource
#数据源唯一标识
spring.datasource.def.unique-resource-name=defDataSource
#数据源opencart1
spring.datasource.opencart1.xa-properties.url=jdbc:mysql://localhost:3307/opencart1?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&rewriteBatchedStatements=true
spring.datasource.opencart1.xa-properties.username=opencart1
spring.datasource.opencart1.xa-properties.password=uorejwrew
spring.datasource.opencart1.xa-data-source-class-name=com.alibaba.druid.pool.xa.DruidXADataSource
#数据源唯一标识
spring.datasource.opencart1.unique-resource-name=opencart1DataSource
- Mapper要分成两个目录，xml不用，如图所示
Mapper
xml
- 多数据源配置类
package com.yysoft.core.config;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;
import javax.sql.DataSource;
@Configuration
@MapperScan(basePackages = "com.yysoft.core.dao.def", sqlSessionTemplateRef = "defSqlSessionTemplate")//指定包使用的sqlSession
public class DefDSConfig {
@Bean
@ConfigurationProperties(prefix = "spring.datasource.def")
@Primary
public DataSource defDataSource() {
return new AtomikosDataSourceBean();
}
@Bean
@Primary
public SqlSessionFactory defSqlSessionFactory(@Qualifier("defDataSource") DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:com/yysoft/core/dao/def/mapper/*Mapper.xml"));//扫描指定目录的xml
return bean.getObject();
}
@Bean
@Primary
public DataSourceTransactionManager defTransactionManager(@Qualifier("defDataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}
@Bean
@Primary
public SqlSessionTemplate defSqlSessionTemplate(@Qualifier("defSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
这里主数据库要用@Primary注解，或者会报错。
package com.yysoft.core.config;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;
import javax.sql.DataSource;
@Configuration
@MapperScan(basePackages = "com.yysoft.core.dao.opencart1", sqlSessionTemplateRef = "opencart1SqlSessionTemplate")//指定包使用的sqlSession
public class Opencart1DSConfig {
@Bean
@ConfigurationProperties(prefix = "spring.datasource.opencart1")
public DataSource opencart1DataSource() {
return new AtomikosDataSourceBean();
}
@Bean
public SqlSessionFactory opencart1SqlSessionFactory(@Qualifier("opencart1DataSource") DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:com/yysoft/core/dao/opencart1/mapper/*Mapper.xml"));//扫描指定目录的xml
return bean.getObject();
}
@Bean
public DataSourceTransactionManager opencart1TransactionManager(@Qualifier("opencart1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}
@Bean
public SqlSessionTemplate opencart1SqlSessionTemplate(@Qualifier("opencart1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
- 事务管理器配置类
package com.yysoft.core.config;
import com.atomikos.icatch.jta.UserTransactionImp;
import com.atomikos.icatch.jta.UserTransactionManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.jta.JtaTransactionManager;
import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;
@Configuration
public class TransactionManagerConfig {
@Bean
public UserTransaction userTransaction() throws Throwable {
UserTransactionImp userTransactionImp = new UserTransactionImp();
userTransactionImp.setTransactionTimeout(10000);
return userTransactionImp;
}
@Bean
public TransactionManager atomikosTransactionManager() throws Throwable {
UserTransactionManager userTransactionManager = new UserTransactionManager();
userTransactionManager.setForceShutdown(false);
return userTransactionManager;
}
@Bean
@DependsOn({ "userTransaction", "atomikosTransactionManager" })
public PlatformTransactionManager transactionManager() throws Throwable {
JtaTransactionManager manager = new JtaTransactionManager(userTransaction(), atomikosTransactionManager());
return manager;
}
}
- 在Service层使用
通过4和5的配置，总共创建了两个数据源，还有三个事务管理器，分别是主库的事务管理器，次库的事务管理器以及分布式事务管理器。通过@Transactional来控制Service类使用哪个事务管理器，如果是@Transactional，则为主库事务(或@Transactional("defTransactionManager"))，@Transactional("opencart1TransactionManager")，则为次库事务，@Transactional("transactionManager")，则为分布式事务。
package com.yysoft.core.service.impl;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.yysoft.core.dao.def.SysMenuQueryMapper;
import com.yysoft.core.dao.def.SysUserMapper;
import com.yysoft.core.dao.opencart1.OcDownloadMapper;
import com.yysoft.core.model.OcDownload;
import com.yysoft.core.model.SysMenu;
import com.yysoft.core.model.SysUser;
import com.yysoft.core.model.SysUserExample;
import com.yysoft.core.web.model.MenuModel;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.yysoft.core.service.IUserService;
import org.springframework.transaction.annotation.Transactional;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
@Service
@Transactional("transactionManager")//分布式事务
public class UserService implements IUserService {
@Autowired
private SysUserMapper sysUserMapper;
@Autowired
private OcDownloadMapper ocDownloadMapper;
@Override
public void removeUsers(String userIds) {
String[] userIdArr = userIds.split(",");
for (String userId : userIdArr) {
SysUser user = sysUserMapper.selectByPrimaryKey(userId);
user.setState("0");
sysUserMapper.updateByPrimaryKey(user);//主库
}
OcDownload ocDownload = new OcDownload();
ocDownload.setFilename("111");
ocDownload.setMask("000");
ocDownload.setDateAdded(new Date());
ocDownloadMapper.insertSelective(ocDownload);//次库
int i = 1/0;//制造异常
}
}
当执行int i = 1/0;后，主库和次库的事务会同步回滚，从而保证了事务的一致性。
第一次写简书，把自己今天配置的过程写了出来，希望也能帮到一些人。
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