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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。
