在项目配置文件中进行如下参数配置,现以“.yml”类型文件举例：

#druid连接池配置
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    master:
      url: jdbc:log4jdbc:mysql://127.0.0.1:3306/demo?serverTimezone=Hongkong&useSSL=false&characterEncoding=UTF-8&autoReconnect=true
      username: root
      password: 123456
      driver-class-name: net.sf.log4jdbc.DriverSpy
      initial-size: 1
      min-idle: 8
      max-wait: 2000
      max-active: 20
      time-between-eviction-runs-millis: 6000
      min-evictable-idle-time-millis: 30000
      validation-query: SELECT 1
      test-on-borrow: false
      test-on-return: false
      test-while-idle: true
      pool-prepared-statements: true
    slave:
      url: jdbc:log4jdbc:mysql://127.0.0.1:3306/demo?serverTimezone=Hongkong&useSSL=false&characterEncoding=UTF-8&autoReconnect=true
      username: root
      password: 123456
      driver-class-name: net.sf.log4jdbc.DriverSpy
      initial-size: 1
      min-idle: 8
      max-wait: 2000
      max-active: 20
      time-between-eviction-runs-millis: 6000
      min-evictable-idle-time-millis: 30000
      validation-query: SELECT 1
      test-on-borrow: false
      test-on-return: false
      test-while-idle: true
      pool-prepared-statements: true

  特别说明：
  1、数据库驱动器采用net.sf.log4jdbc.DriverSpy（配置请参考：https://blog.csdn.net/xiehd313/article/details/101350567），这样可以很完整地打印出SQL语句，方便在开发环境时调试。但是线上环境不建议使用这个驱动器，因为会消耗一定的内存，线上环境依然使用这个驱动器：com.mysql.cj.jdbc.Driver。

2、强烈注意：Spring Boot 2.X 版本不再支持配置继承，多数据源的话每个数据源的所有配置都需要单独配置，否则配置不会生效。

创建数据源：

 /**
     * 主库配置
     */
    @Bean(name = "masterDataSource", destroyMethod = "close", initMethod = "init")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    @Primary
    public DruidDataSource createMasterSource() {
        return DruidDataSourceBuilder.create().build();
    }

    /**
     * 从库配置
     */
    @Bean(name = "slaveDataSource", destroyMethod = "close", initMethod = "init")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DruidDataSource createSlaveSource() {
        return DruidDataSourceBuilder.create().build();
    }

更多配置(如：动态切换)请参考：https://blog.csdn.net/WayneLee0809/article/details/91373780