SpringBoot+Mybatis多数据源配置和切换

前言

在项目开发中，经常会涉及到一个应用程序调用多个数据的情况。今天介绍一个SpringBoot+mybatis的多数据源的解决方案。

数据库准备

创建两个数据库，两个数据库都有Im_person表，两个表中无数据。

代码结构

说明：我这里只是为了体现效果，就省略了service步骤。各位大牛开发，不喜勿喷，理解万岁，嘻嘻！！

1. application.yml中配置两个数据源，配置如下：

master:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/db1?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowMultiQueries=true&serverTimezone=GMT%2B8
    username: root
    password: 123456

slave:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/db2?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowMultiQueries=true&serverTimezone=GMT%2B8
    username: root
    password: 123456

2.SpringBoot多数据源配置类。

@Configuration
@MapperScan(basePackages = "com.zhangls.multipledatasource.dao.master", sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterDataSourceConfig {
    @Value("${master.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${master.datasource.url}")
    private String url;

    @Value("${master.datasource.username}")
    private String username;

    @Value("${master.datasource.password}")
    private String password;

    @Bean(name = "masterDataSource")
    @Primary
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "masterSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
        List<String> mapperLocations = new ArrayList<>();
        mapperLocations.add("classpath*:/mapper/master/*.xml");
        List<Resource> resources = new ArrayList();
        if (mapperLocations != null) {
            for (String mapperLocation : mapperLocations) {
                try {
                    Resource[] mappers = resourceResolver.getResources(mapperLocation);
                    resources.addAll(Arrays.asList(mappers));
                } catch (IOException e) {
                    // ignore
                }
            }
        }

        bean.setMapperLocations(resources.toArray(new Resource[resources.size()]));
        return bean.getObject();
    }

    @Bean(name = "masterTransactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("masterDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "masterSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(
            @Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

@Configuration
@MapperScan(basePackages = "com.zhangls.multipledatasource.dao.slave", sqlSessionFactoryRef = "slaveSqlSessionFactory")
public class SlaveDataSourceConfig {
    @Value("${slave.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${slave.datasource.url}")
    private String url;

    @Value("${slave.datasource.username}")
    private String username;

    @Value("${slave.datasource.password}")
    private String password;

    @Bean(name = "slaveDataSource")
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(@Qualifier("slaveDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/slave/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "slaveTransactionManager")
    public DataSourceTransactionManager transactionManager(@Qualifier("slaveDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "slaveSqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(
            @Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

说明：两个数据的代码基本相同，不同的是要配置好扫描包的路径，以及mybatis的SQL文件的路径。所以不同的连接DAO和mapper文件要放在不同的文件夹，方便配置管理。

实现效果

以上的配置已经实现了多数据源的配置，下面实现一个功能。通过一个接口同时向两个库的两个表中导入不同的数据。

controller代码如下：

@RestController
public class DataSourceController {
    @Resource
    private MasterPersonMapper masterPersonMapper;
    @Resource
    private SlavePersonMapper slavePersonMapper;

    @GetMapping("/datasource")
    public String datasource() {
        ImPerson person1 = new ImPerson();
        person1.setPersonId("1");
        person1.setGender("男");
        person1.setBirthday(new Date());
        person1.setLocation("中国");
        masterPersonMapper.insertSelective(person1);

        ImPerson person2 = new ImPerson();
        person2.setPersonId("2");
        person2.setGender("女");
        person2.setBirthday(new Date());
        person2.setLocation("中国北京");
        slavePersonMapper.insertSelective(person2);
        return "导入成功";
    }
}

执行：

结果：

可以看到两个库中的两个表都导入了数据。