Spring Boot配置MyBatis多数据源

前言

配置多数据源，即在大型应用中对数据进行切分，并且采用多个数据库实例进行管理，这样可以有效提高系统的水平伸缩性。

数据源属性配置

如需配置2个数据源则要在application.yml文件中进行如下配置：

spring:
  datasource:
    one:
      username: db1
      password: 123456
      jdbc-url: jdbc:mysql://localhost/db1
    two:
      username: db2
      password: 123456
      jdbc-url: jdbc:mysql://localhost/db2

数据源属性注入

新建DataSourceConfig类管理多个数据源将配置的属性进行注入并生成Bean

@Configuration
public class DataSourceConfig {

    /**
     * 数据源1
     */
    @Bean
    @ConfigurationProperties("spring.datasource.one")
    public DataSource dsOne() {
        return DataSourceBuilder.create().build();
    }

    /**
     * 数据源2
     */
    @Bean
    @ConfigurationProperties("spring.datasource.two")
    public DataSource dsTwo() {
        return DataSourceBuilder.create().build();
    }
}

MyBatis配置

新建MyBatisOneConfig和MyBatisTwoConfig管理数据源1和数据源2
@MapperScan注解使对应包下的Mapper使用对应的SqlSessionFactory实例

@Configuration
@MapperScan(value = "com.example.demo.mapper.one", sqlSessionFactoryRef = "sqlSessionFactoryBean1")
public class MyBatisOneConfig {

    @Resource
    @Qualifier("dsOne")
    private DataSource dsOne;

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean1() throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dsOne);
        return factoryBean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate1() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactoryBean1());
    }
}

@Configuration
@MapperScan(value = "com.example.demo.mapper.two", sqlSessionFactoryRef = "sqlSessionFactoryBean2")
public class MyBatisTwoConfig {

    @Resource
    @Qualifier("dsTwo")
    private DataSource dsTwo;

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean2() throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dsTwo);
        return factoryBean.getObject();
    }

    @Bean
    public SqlSessionTemplate sqlSessionTemplate2() throws Exception {
        return new SqlSessionTemplate(sqlSessionFactoryBean2());
    }
}

若需要将XML映射文件写在resources目录下可添加如该段代码

  org.springframework.core.io.Resource[] resources = new PathMatchingResourcePatternResolver()
                .getResources("classpath:/mapping/one/*.xml");
  factoryBean.setMapperLocations(resources);

创建Mapper和对应的映射文件

在one和two包下创建mapper和对应的映射文件

1.png

在Maven工程中，XML配置文件建议写在resources目录下但上下文的Mapper.xml文件写在包下,Maven在运行时会忽略包下的XML文件，因此需要在pom.xml文件中指明资源文件位置，配置如下

    <build>
        ...
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
        ...
    </build>

注入实例并调用

@RestController
public class DemoController {

    @Resource
    private BookMapper bookMapper;

    @Resource
    private BrandListMapper brandListMapper;

    @RequestMapping("/book")
    public String getBook() {
        return JSON.toJSONString(bookMapper.findAll());
    }

    @RequestMapping("/brandlist")
    public String getBrandList() {
        return JSON.toJSONString(brandListMapper.findAll());
    }
}