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>

&lt;<span class="hljs-keyword">select</span> id=<span class="hljs-string">"findAuthorityByUrl"</span> resultType=<span class="hljs-string">"java.lang.String"</span> databaseId=<span class="hljs-string">"postgresql"</span>&gt;
    <span class="hljs-function">SELECT
    <span class="hljs-title">string_agg</span>(<span class="hljs-params"> tsma.authority, <span class="hljs-string">','</span></span>) <span class="hljs-keyword">as</span> authority
    FROM
    t_side_menu tsm
    LEFT JOIN t_side_menu_authority tsma ON tsm.id</span> = tsma.side_menu_id
&lt;/<span class="hljs-keyword">select</span>&gt;</code></pre>

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。

原文地址：https://segmentfault.com/a/1190000018193491?utm_source=tag-newest

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