SpringBoot+Mybatis多数据库

配置application.yaml数据源

在application.yaml中配置数据源，也可使用多环境profiles切换

spring:
  datasource:
    jdbc-url: jdbc:mysql://192.168.1.26:3306/test?characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: root
    password: root

#    jdbc-url: jdbc:dm://192.168.1.19:5238/test
#    username: username
#    password: password

数据源配置类

@Configuration
public class DataSourceConfig {
    @Value("${mybatis.mapper-locations}")
    private String mapperLocations;

    @Primary
    @Bean(name = "dataSource")
    @ConfigurationProperties("spring.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
    public JdbcTemplate jdbcTemplate() {
        return new JdbcTemplate(dataSource());
    }

    @Bean
    public DatabaseIdProvider databaseIdProvider() {
        DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();
        Properties p = new Properties();
        p.setProperty("Oracle", "oracle");
        p.setProperty("MySQL", "mysql");
        p.setProperty("PostgreSQL", "postgresql");
        p.setProperty("DM DBMS", "dm");
        p.setProperty("SQL Server", "sqlserver");
        databaseIdProvider.setProperties(p);
        return databaseIdProvider;
    }

    @Primary
    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(@Qualifier("dataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        factoryBean.setDatabaseIdProvider(databaseIdProvider());
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
        return factoryBean;
    }
}

编写mapper.xml

<!--
    <select id="selectByPrimaryKey" parameterType="java.lang.String" resultMap="BaseResultMap" databaseId="mysql">
        select account
        from SYS_USER
        where ID = #{id,jdbcType=CHAR}
    </select>
    
    <select id="selectByPrimaryKey" parameterType="java.lang.String" resultMap="BaseResultMap" databaseId="dm">
        select dep_code
        from SYS_USER
        where ID = #{id,jdbcType=CHAR}
    </select>
-->

或

  <select id="selectByPrimaryKey" parameterType="java.lang.String" resultMap="BaseResultMap">
        select
        <if test="_databaseId == 'mysql'">
          account
        </if>
        <if test="_databaseId == 'dm'">
          dep_code
        </if>
        from SYS_USER
        where ID = #{id,jdbcType=CHAR}
  </select>