Java EE7：@DatasourceDefinition，如何参数化值？

Question

I am learning how to use @DataSourceDefinition . The documentation gives a specific example as

 @DataSourceDefinition(name="java:global/MyApp/MyDataSource",
      className="com.foobar.MyDataSource",
      portNumber=6689,
      serverName="myserver.com",
      user="lance",
      password="secret"
   )

Question
How can I substitute these values for environment variables? like DB_HOST , DB_URL

The reason is when I deploy my application to providers like OPENSHIFT , all I get the values to use to connect to database.

I would not like to hardcode them in my codebase. This adds coupling to particular database and can not be switched at runtime

Any ideas?

Answer 1

If you want to deploy a Java EE application in OPENSHIFT as well as in your LOCAL JBoss then it's recommended to use the JBoss configuration file to configure the datasource properties and use that datasouce JNDI name in your persistence.xml .

Refer : https://help.openshift.com/hc/en-us/articles/202964690-Default-database-connectivity-configurations-for-JBoss-Applications

If you really don't want to use the application server (like JBoss) specific configurations. Then you can write a data source wrapper for @DataSourceDefinition annotated class and change the value from of the data source using a external property file.

Refer : http://jdevelopment.nl/switching-data-sources-datasourcedefinition