How to set custom connection properties on DataSource in Spring Boot 1.3.x with default Tomcat connection pool

Question

I need to set some specific Oracle JDBC connection properties in order to speed up batch INSERTs (defaultBatchValue) and mass SELECTs

Answer 1

As Spring Boot is EOL for a long time I switched to Spring Boot 2.1 with its new default connection pool Hikari. Here the solution is even more simply and can be done in the application.properties or (like shown here) application.yml:

spring:
  datasource:
    hikari:
      data-source-properties:
        defaultRowPrefetch: 1000

(In a real-life config there would be several other configuration items but as they are not of interest for the question asked I simply left them out in my example)