Atomikos解决多数据源事务

参考地址：分布式事务

一、引入maven依赖

 <!--添加atomikos-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jta-atomikos</artifactId>
        </dependency>
        <!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.0</version>
        </dependency>
        <!-- druids数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.8</version>
        </dependency>

二、配置多数据源

1、application.yml数据源配置

#数据源配置
spring:
  datasource:
    #第一个数据源配置：名字自定义
    first:
     url: jdbc:postgresql://192.168.1.198:5432/datacenter?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true&useSSL=false&pinGlobalTxToPhysicalConnection=true
     username: datacenter
     password: datacenter
    #第二个数据源配置：名字自定义 
    second:
      url: jdbc:postgresql://192.168.1.198:5432/government?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true&useSSL=false&pinGlobalTxToPhysicalConnection=true
      username: government
      password: government@123

2、Java配置数据源

分开两个文件配置，清晰明了，不易出错。

first数据源

@Configuration
@MapperScan(basePackages = {"com.yzh.demo.mapper.first"},sqlSessionTemplateRef = "firstSqlSessionTemplate")
public class DataSourceConfig1 {

    @Value("${spring.datasource.first.url}")
    private String url;
    @Value("${spring.datasource.first.username}")
    private String username;
    @Value("${spring.datasource.first.password}")
    private String password;

    /**
     * 创建first数据源
     */
    @Bean(name = "firstDataSource")
    @Primary
    public DataSource createProductDataSource(){
        AtomikosDataSourceBean ds = new AtomikosDataSourceBean();
        DruidXADataSource dds = new DruidXADataSource();
        dds.setUsername(username);
        dds.setPassword(password);
        dds.setUrl(url);
        ds.setXaDataSource(dds);
        ds.setUniqueResourceName("firstDataSource");
        return ds;
    }

    @Primary
    @Bean(name = "firstSqlSessionFactory")
    public SqlSessionFactory firstSqlSessionFactory(@Qualifier(value = "firstDataSource") DataSource dataSource) throws Exception {
        //这里如果使用SqlSessionFactoryBean 将不能使用mybatis-plus自带的baseMapper中的方法
        MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        //设置数据源
        sqlSessionFactoryBean.setDataSource(dataSource);
        //设置别名
        sqlSessionFactoryBean.setTypeAliasesPackage("com.yzh.demo.entity.first");
        //设置驼峰
        MybatisConfiguration c = new MybatisConfiguration();
        c.setMapUnderscoreToCamelCase(true);
        sqlSessionFactoryBean.setConfiguration(c);
        //设置映射接口的xml配置文件
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/first/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }

    /**
     * 创建SqlSessionTemplate
     */
    @Primary
    @Bean(name = "firstSqlSessionTemplate")
    public SqlSessionTemplate firstSqlSessionTemplate(@Qualifier("firstSqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

second数据源

@Configuration
@MapperScan(basePackages = {"com.yzh.demo.mapper.second"},sqlSessionTemplateRef = "secondSqlSessionTemplate")
public class DataSourceConfig2 {

    @Value("${spring.datasource.second.url}")
    private String url;
    @Value("${spring.datasource.second.username}")
    private String username;
    @Value("${spring.datasource.second.password}")
    private String password;

    /**
     * 创建second数据源
     */
    @Bean(name = "secondDataSource")
    public DataSource createProductDataSource(){
        AtomikosDataSourceBean ds = new AtomikosDataSourceBean();
        DruidXADataSource dds = new DruidXADataSource();
        dds.setUsername(username);
        dds.setPassword(password);
        dds.setUrl(url);
        ds.setXaDataSource(dds);
        ds.setUniqueResourceName("secondDataSource");
        return ds;
    }

    @Bean(name = "secondSqlSessionFactory")
    public SqlSessionFactory orderSqlSessionFactory(@Qualifier(value = "secondDataSource") DataSource dataSource) throws Exception {
        //这里如果使用SqlSessionFactoryBean 将不能使用mybatis-plus自带的baseMapper中的方法
        MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        //设置数据源
        sqlSessionFactoryBean.setDataSource(dataSource);
        //设置别名
        sqlSessionFactoryBean.setTypeAliasesPackage("com.yzh.demo.entity.second");
        //设置驼峰
        MybatisConfiguration c = new MybatisConfiguration();
        c.setMapUnderscoreToCamelCase(true);
        sqlSessionFactoryBean.setConfiguration(c);
        //设置映射接口的xml配置文件
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/second/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }

    /**
     * 创建SqlSessionTemplate
     */
    @Bean(name = "secondSqlSessionTemplate")
    public SqlSessionTemplate orderSqlSessionTemplate(@Qualifier("secondSqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

3、业务代码

实体类略。

@Service
public class Test1ServiceImpl extends ServiceImpl<Test1Mapper, Test1> implements ITest1Service {


    @Autowired
    private Test2Mapper test2Mapper;
    @Autowired
    private Test1Mapper test1Mapper;

    @Transactional
    @Override
    public void test(Integer id,Integer num) {
        //先插入first库
        Test1 t1 = new Test1();
        t1.setId(id);
        t1.setNum(num);
        test1Mapper.insert(t1);

        //再插入second库
        Test2 t2 = new Test2();
        t2.setId(id);
        t2.setNum(num);
        test2Mapper.insert(t2);
        //抛出异常
        int i = 1 / 0;
    }
}

 4、注意

当遇到入校错误时：

Caused by: org.postgresql.util.PSQLException: ERROR: prepared transactions are disabled

说明参数max_prepared_transactions=0，关闭了预准备事务，需要在postgresql.conf中将该参数的值设置大于1（建议设置成和max_connections一致）