title: Spring Boot: Read Datasource properties from another property file
body: <p>I want to configure a tomcat data source in Spring Boot, The properties of the database are stored in another property file (Say dbConnection.properties) with different keys.</p>
  
  <p>For example </p>
  
  <p><strong>dbConnection.properties:</strong></p>
  
  <pre><code>DATABASE_URL=SomeURL
  DATABASE_USER=SomeUser
  DATABASE_PASSWORD=SomePassword
  </code></pre>
  
  <p>From what I understand the properties related to a data source must be specified in <strong>application.properties</strong> as:</p>
  
  <pre><code>spring.datasource.url=jdbc:mysql://localhost/test
  spring.datasource.username=dbuser
  spring.datasource.password=dbpass
  </code></pre>
  
  <p>How do I pass the values from dbConnection.properties to application.properties?</p>