Spring-Boot: How do I set JDBC pool properties like maximum number of connections?

Question

Spring-Boot is a pretty awesome tool, but the documentation is a bit sparse when it comes to more advanced configuration. How can I set properties like the maximum size for

Answer 1

Different connections pools have different configs.

For example Tomcat (default) expects:

spring.datasource.ourdb.url=...

and HikariCP will be happy with:

spring.datasource.ourdb.jdbc-url=...

We can satisfy both without boilerplate configuration:

spring.datasource.ourdb.jdbc-url=${spring.datasource.ourdb.url}

---

There is no property to define connection pool provider.

Take a look at source DataSourceBuilder.java

If Tomcat, HikariCP or Commons DBCP are on the classpath one of them will be selected (in that order with Tomcat first).

... so, we can easily replace connection pool provider using this maven configuration (pom.xml):

    
        org.springframework.boot
        spring-boot-starter-jdbc
        
            
                org.apache.tomcat
                tomcat-jdbc
            
        
           

    
        com.zaxxer
        HikariCP