Springboot 集成 dynamic-datasource-spring-boot-starter，实现项目中原有的数据源作为主数据源

Springboot 集成 dynamic-datasource-spring-boot-starter，实现项目中原有的数据源作为主数据源

保证原有项目中在执行数据库操作时，默认使用原有数据源，新数据源做特定操作

引入多数据源切换依赖：

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>3.6.1</version>
</dependency>

使用的数据库连接池依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.15</version>
</dependency>

<!-- 使用这个也没有问题，都是druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.12</version>
</dependency>

以下相关代码编写基于的配置文件：

mysql: &db-mysql
  username: 'xxxx'
  password: 'xxxxx'
  driverClassName: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/xxxxx?serverTimezone=Asia/Shanghai&characterEncoding=utf8&useUnicode=true&useSSL=false&autoReconnect=true&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&nullCatalogMeansCurrent=true

spring:
  datasource:
  	# << 用法解释：引用变量的作用  引用已提前定义好的配置：db-mysql 即最上面的配置
  	# 使用后的配置为：
  	# db-type: mysql
  	# validation-query: SELECT 'x'
  	# filters: stat,wall
  	# username: 'xxxx'
  	# password: 'xxxxx'
  	# driverClassName: com.mysql.cj.jdbc.Driver
  	# url: jdbc:mysql://localhost:3306/xxxxx?serverTimezone=Asia/Shanghai&characterEncoding=utf8&useUnicode=true&useSSL=false&autoReconnect=true&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&nullCatalogMeansCurrent=true
    <<: *db-mysql

动态数据源配置类

@Configuration
@EnableConfigurationProperties({DynamicDataSourceProperties.class})
@AutoConfigureBefore({DynamicDataSourceAutoConfiguration.class, SpringBootConfiguration.class})
public class DataSourceConfiguration {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    /**
     * 动态数据源配置项
     */
    @Autowired
    private DynamicDataSourceProperties properties;
    @Autowired
    private DataSourceProperties dataSourceProperties;

    @Bean
    public DynamicDataSourceProvider dynamicDataSourceProvider() {
        //todo 可以做更多的事情，例如从spring容器中获取已创建好的数据源对象，来由动态数据源管理，等等
        
        //默认使用spring提供的数据源信息来创建默认数据源
        DataSourceProperty masterProperty = new DataSourceProperty();
        masterProperty.setType(dataSourceProperties.getType())
            .setDriverClassName(dataSourceProperties.getDriverClassName())
            .setUrl(dataSourceProperties.getUrl())
            .setUsername(dataSourceProperties.getUsername()).setPassword(dataSourceProperties.getPassword());
        //多数据源的数据源信息配置是否存在，如果存在则保存
        Map<String, DataSourceProperty> datasource = properties.getDatasource();
        if(!datasource.isEmpty()){
            //如果存在指定了默认数据源，则替换spring的数据源信息
            DataSourceProperty dynamicMasterProperty = datasource.get(properties.getPrimary());
            if(dynamicMasterProperty != null){
                masterProperty.setType(dynamicMasterProperty.getType())
                    .setDriverClassName(dynamicMasterProperty.getDriverClassName())
                    .setUrl(dynamicMasterProperty.getUrl()).setUsername(dynamicMasterProperty.getUsername())
                    .setPassword(dynamicMasterProperty.getPassword());
            }
        }

        return new CustomDataSourceProvider(masterProperty,properties);
    }

    /**
     * 将动态数据源设置为首选的
     * 当spring存在多个数据源时, 自动注入的是首选的对象
     * 设置为主要的数据源之后，就可以支持shardingjdbc原生的配置方式了
     * @return
     */
    @Primary
    @Bean
    public DataSource dataSource() {
        DynamicRoutingDataSource dataSource = new DynamicRoutingDataSource();
        dataSource.setPrimary(properties.getPrimary());
        dataSource.setStrict(properties.getStrict());
        dataSource.setStrategy(properties.getStrategy());
        dataSource.setP6spy(properties.getP6spy());
        dataSource.setSeata(properties.getSeata());
        return dataSource;
    }
}

继承AbstractDataSourceProvider类，实现loadDataSources方法

@AllArgsConstructor
public class CustomDataSourceProvider extends AbstractDataSourceProvider {

    private final DataSourceProperty masterProperty;
    private final DynamicDataSourceProperties dynamicDataSourceProperties;

    @Override
    public Map<String, DataSource> loadDataSources() {
        Map<String, DataSourceProperty> map = new HashMap(16);
        masterProperty.setDruid(this.dynamicDataSourceProperties.getDruid());
        map.put(this.dynamicDataSourceProperties.getPrimary(), masterProperty);

        Map<String, DataSourceProperty> datasource = this.dynamicDataSourceProperties.getDatasource();
        if (!datasource.isEmpty()) {
            map.putAll(datasource);
        }

        Map<String, DataSource> dataSourceMap = this.createDataSourceMap(map);
        return dataSourceMap;
    }
}