SpringBoot+MyBatis（动态数据源/分布式事务XA(Atomikos)）

说明

适用环境：SpringBoot / MyBatis / Atomickos
特性：

多数据源，动态切换
多数据源，XA分布式事务支持(需引入Atomickos)

仅支持Mybatis,采用AbstractRoutingDataSource实现数据源动态切换。引入Atomickos分布式事务，可支持多数据源动态切换分布式事务。

使用方法

引入jar包依赖 maven:

      <dependency>
        <groupId>com.tomz</groupId>
        <artifactId>xatomic</artifactId>
        <version>1.0.0</version>
      </dependency>

gradle:

implementation 'com.tomz:xatomic:1.0.0'

使用注解切换数据源@DynamicDataSource,可以放在类或者方法上。

多数据源功能
配置文件示例：对于name属性，当数据源集合中存在name=default的数据源时，该数据源作为默认数据源，不加@DynamicDataSource默认使用该数据源，否则取集合中的第一个数据源作为默认数据源

  spring:
      datasources:
        - name: ds1
          type: com.zaxxer.hikari.HikariDataSource
          username: root
          password:
          driver-class-name: com.mysql.cj.jdbc.Driver
          jdbcUrl: jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf-8&useSSL=false&autoReconnect=true&allowMultiQueries=true&&serverTimezone=GMT%2B8
        - name: ds2
          type: com.zaxxer.hikari.HikariDataSource
          username: root
          password:
          driver-class-name: com.mysql.cj.jdbc.Driver
          jdbcUrl: jdbc:mysql://localhost:3306/test02?useUnicode=true&characterEncoding=utf-8&useSSL=false&autoReconnect=true&allowMultiQueries=true&&serverTimezone=GMT%2B8

多数据源XA分布式事务支持
引入： implementation 'org.springframework.boot:spring-boot-starter-jta-atomikos' 配置文件与多数据源配置文件相似，但是数据源类型type需要改为支持XA的数据源对象, 如：MysqlXADataSource，DruidXADataSource。需要注意的是，对于DruidXADataSource，支持的MySql驱动类型当前只到8.0.11版本。

 spring:
     datasources:
       - name: ds1
         type: com.mysql.cj.jdbc.MysqlXADataSource
         databaseName: test01
         hostName: localhost
         user: root
         password:
         port: 3306
         url: jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf-8&useSSL=false&autoReconnect=true&allowMultiQueries=true&&serverTimezone=GMT%2B8
       - name: ds2
         type: com.mysql.cj.jdbc.MysqlXADataSource
         databaseName: test01
         hostName: localhost
         user: root
         password:
         port: 3306
         url: jdbc:mysql://localhost:3306/test02?useUnicode=true&characterEncoding=utf-8&useSSL=false&autoReconnect=true&allowMultiQueries=true&&serverTimezone=GMT%2B8

此外还可以对Atomickos做配置

 # JtaProperties
 spring.jta:
 #  logDir:
   transactionManagerId: myTxMgrId
   # AtomikosProperties
 #  atomikos:
 #    properties:
   # org.springframework.boot.jta.atomikos.AtomikosDataSourceBean 数据源连接池配置
   atomikos:
     datasource:
       poolSize: 5
       minPoolSize: 3
       maxPoolSize: 20
       borrowConnectionTimeout: 60
       reapTimeout: 300
       maxIdleTime: 60
       maintenanceInterval: 60
       loginTimeout: 60
       testQuery: select 1

最后，需要在Configuration类上面使用MapperScan注解，如下：

 //factoryBean替换掉默认的MapperFactoryBean，实现Mapper映射到每个数据源。仅使用xa分布式事务支持才需要添加该注解，否则只用多数据源功能可以不加
 @MapperScan(factoryBean = XaDynamicMapperFactoryBean.class, basePackages = {"com.test.mapper"}) 
 @SpringBootApplication 
 class ApplicationDemo { 
    public static void main(String[] args) {
    		SpringApplication.run(ApplicationDemo.class, args);
    	}   
 }
 //mapper类
 @Mapper
 public interface TestMapper {  
     @DynamicDataSource("ds1")
     @Insert("insert into test(name) values ('a')")
     long insertA();
 
     @DynamicDataSource("ds2")
     @Insert("insert into test(name) values ('b')")
     long insertB();
 }
 //service类
 @Service
 class ServiceA {
       @Autowired
       private TestMapper mapper;
       @Transactional(rollbackFor = Exception.class)
       public void insertAB() {
           this.mapper.insertA();
           this.mapper.insertB();
           //throw new IllegalArgumentException("test xa-rollback");
       }
 }
 //测试类
 @RunWith(SpringRunner.class)
 @SpringBootTest
 public class ServiceTest {
 
     @Autowired
     private ServiceA service;
 
     @Test
     public void testXa() {
         this.service.insertAB();
     }
 
 }

禁用分布式事务数据源：spring.jta.enabled=false
禁用动态多数据源：spring.dynamic.datasouce.enabled=false

备注：该项目需要自己下载到本地，执行install安装到本地才能引用。?

    $ git clone https://gitee.com/t0mZ/xatomic.git
    Initialized empty Git repository in D:/java/xatomic/.git/
    remote: Enumerating objects: 69, done.
    remote: Counting objects: 100% (69/69), done.
    remote: Compressing objects: 100% (56/56), done.
    remote: Total 69 (delta 19), reused 0 (delta 0)
    Unpacking objects: 100% (69/69), done.
    $ cd xatomic
    $ ./gradlew install
    Downloading https://services.gradle.org/distributions/gradle-4.10.3-all.zip
    ................................................................................................................
    Unzipping /home/.gradle/wrapper/dists/gradle
    ...省略....
    > Task :compileJava
    Note: Some input files use unchecked or unsafe operations.
    Note: Recompile with -Xlint:unchecked for details.
    
    BUILD SUCCESSFUL in 2m 15s
    4 actionable tasks: 4 executed