Spring Boot配置多数据源并实现Druid自动切换

原文：https://blog.csdn.net/acquaintanceship/article/details/75350653

Spring Boot配置多数据源
配置yml文件
主数据源配置
从数据源配置
使用dao
日志
Spring Boot配置多数据源
配置yml文件
这里并没有对spring.datasource配置数据源，因为增加新数据源后，系统会覆盖由spring.datasource自动配置的内容。
这里自定义了两个数据源spring.datasource.cmmi和spring.datasource.zentao

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    base:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: com.mysql.cj.jdbc.Driver
      initialize: true #指定初始化数据源，是否用data.sql来初始化，默认: true
      name: cmmi
      url: jdbc:mysql://127.0.0.1:3306/cmmi?useUnicode=true&characterEncoding=utf-8&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&zeroDateTimeBehavior=convertToNull
      username: root
      password: root
    zentao:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: com.mysql.cj.jdbc.Driver
      initialize: true
      name: zentaopro
      url: jdbc:mysql://127.0.0.1:3306/zentaopro?useUnicode=true&characterEncoding=utf-8&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&zeroDateTimeBehavior=convertToNull
      username: root
      password: root

主数据源配置
注意，配置类需要对DataSource、DataSourceTransactionManager、SqlSessionFactory 、SqlSessionTemplate四个数据项进行配置；DataSource类型需要引入javax.sql.DataSource；当系统中有多个数据源时，必须有一个数据源为主数据源，使用@Primary修饰。
@MapperScan对指定dao包建立映射，确保在多个数据源下，自动选择合适的数据源，而在service层里不需要做特殊说明。

@Configuration
@MapperScan(basePackages = "cmmi.dao.base", sqlSessionTemplateRef = "baseSqlSessionTemplate")
public class BaseDataSourceConfig {
    @Bean(name = "baseDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.base")
    @Primary
    public DataSource setDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "baseTransactionManager")
    @Primary
    public DataSourceTransactionManager setTransactionManager(@Qualifier("baseDataSource") DataSource dataSource) {
        return new DruidDataSource();
    }

    @Bean(name = "baseSqlSessionFactory")
    @Primary
    public SqlSessionFactory setSqlSessionFactory(@Qualifier("baseDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/base/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "baseSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate setSqlSessionTemplate(@Qualifier("baseSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

从数据源配置

@Configuration
@MapperScan(basePackages = "cmmi.dao.zentao", sqlSessionTemplateRef = "zentaoSqlSessionTemplate")
public class ZentaoDataSourceConfig {
    @Bean(name = "zentaoDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.zentao")
    public DataSource setDataSource() {
        return new DruidDataSource();
    }

    @Bean(name = "zentaoTransactionManager")
    public DataSourceTransactionManager setTransactionManager(@Qualifier("zentaoDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

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

    @Bean(name = "zentaoSqlSessionTemplate")
    public SqlSessionTemplate setSqlSessionTemplate(@Qualifier("zentaoSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

使用dao

这里只需要正常使用dao就可以了，spring会根据数据源配置的映射自动选择相应数据源，而不需要在service做特殊说明。

@Service
public class TestService {
    private final ZtUserMapper ztUserMapper;
    private final LevelDic levelDic;

    @Autowired
    public TestService(ZtUserMapper ztUserMapper, LevelDic levelDic) {
        this.ztUserMapper = ztUserMapper;
        this.levelDic = levelDic;
    }

    public void test() {
        ztUserMapper.selectByPrimaryKey(1);
        levelDic.setDicId(new Integer(1).byteValue());
    }
}

日志

o.a.c.c.C.[Tomcat].[localhost].[/cmmi] : Initializing Spring FrameworkServlet ‘dispatcherServlet’ 
o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet’: initialization started 
o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet’: initialization completed in 23 ms 
com.alibaba.druid.pool.DruidDataSource : {dataSource-1,cmmi} inited 
com.alibaba.druid.pool.DruidDataSource : {dataSource-2,zentaopro} inited