How to Configure to Two DataSources (Databases) in Spring Boot Application?

If you want to make use of two databases in your Spring Boot application, then you can follow the below steps,

Step 1: Add Two DataSource Configuration in application.properties file

# First Oracle DataSource Configuration
spring.datasource.first.url=jdbc:oracle:thin:@localhost:1521:db1
spring.datasource.first.username=user
spring.datasource.first.password= password
spring.datasource.first.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.datasource.first.jpa.hibernate.ddl-auto=update

# Second MySQL DataSource Configuration
spring.datasource.second.url=jdbc:mysql://localhost:3306/db2
spring.datasource.second.username=root
spring.datasource.second.password=password
spring.datasource.second.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.second.jpa.hibernate.ddl-auto=update 

If you are using application.yml

# First Oracle DataSource Configuration
spring:
  datasource:
    first:
      url: jdbc:oracle:thin:@localhost:1521:db1
      username: user
      password: password
      driver-class-name: oracle.jdbc.driver.OracleDriver
      jpa:
        hibernate:
          ddl-auto: update

# Second MySQL DataSource Configuration
  datasource:
    second:
      url: jdbc:mysql://localhost:3306/db2
      username: root
      password: password
      driver-class-name: com.mysql.cj.jdbc.Driver
      jpa:
        hibernate:
          ddl-auto: update

Step 2: Add your beans in your Configuration Java file

@Bean
@Primary
@ConfigurationProperties(prefix="spring.datasource.first")
public DataSource primaryDataSource() {
    return DataSourceBuilder.create().build();
}

@Bean
@ConfigurationProperties(prefix="spring.datasource.second")
public DataSource secondaryDataSource() {
    return DataSourceBuilder.create().build();
}