Spring Boot MyBatis配置多种数据库

mybatis-config.xml是支持配置多种数据库的，本文将介绍在Spring Boot中使用配置类来配置。

1. 配置application.yml

# mybatis配置
mybatis:
check-config-location: false
type-aliases-package: ${base.package}.model
configuration:
map-underscore-to-camel-case: true
# 二级缓存的总开关
cache-enabled: false
mapper-locations: classpath:mapping/*.xml


2. 新增数据源配置类

/**
* 数据源配置
* @author simon
* @date 2019-02-18
*/
@Configuration
public class DataSourceConfig {
@Value("${mybatis.mapper-locations}")
private String mapperLocations; @Primary
@Bean
@ConfigurationProperties("spring.datasource.druid")
public DataSource dataSource(){
return DruidDataSourceBuilder.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("DB2", "db2");
p.setProperty("SQL Server", "sqlserver");
databaseIdProvider.setProperties(p);
return databaseIdProvider;
} @Bean
public SqlSessionFactoryBean sqlSessionFactoryBean() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dataSource());
factoryBean.setDatabaseIdProvider(databaseIdProvider());
factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
return factoryBean;
}
}

3. 在mapper.xml中使用

方法1

<select id="findAuthorityByUrl" resultType="java.lang.String" databaseId="mysql">
SELECT
group_concat( tsma.authority ) as authority
FROM
t_side_menu tsm
LEFT JOIN t_side_menu_authority tsma ON tsm.id = tsma.side_menu_id
</select> <select id="findAuthorityByUrl" resultType="java.lang.String" databaseId="postgresql">
SELECT
string_agg( tsma.authority, ',') as authority
FROM
t_side_menu tsm
LEFT JOIN t_side_menu_authority tsma ON tsm.id = tsma.side_menu_id
</select>


方法2

<select id="selectByPids" parameterType="String" resultMap="SuperResultMap">
SELECT
tsm.*,
<if test="_databaseId == 'mysql'">
group_concat( tsma.authority ) as authority
</if>
<if test="_databaseId == 'postgresql'">
string_agg( tsma.authority, ',') as authority
</if>
FROM
t_side_menu tsm
LEFT JOIN t_side_menu_authority tsma ON tsm.id = tsma.side_menu_id
WHERE pid IN (#{pids})
GROUP BY
tsm.id
</select>


题外话

如果有兴趣，请给oauthserer项目一个star。oauthserver是一个基于Spring Boot Oauth2的完整的独立的Oauth2 Server微服务。项目的目的是，仅仅需要创建相关数据表，修改数据库的连接信息，你就可以得到一个Oauth2 Server微服务。