Better scalability and maintenance
For DriverManager
you need to know all the details (host, port, username, password, driver class) to connect to DB and to get connections. Externalizing those in a properties file doesn't change anything about the fact that you need to know them.
Using a DataSource
you only need to know the JNDI name. The AppServer cares about the details and is not configured by the client application's vendor, but by an admin where the application is hosted.
Scalability:
Suppose you need to create connections yourself, how would you deal with changing load, sometime you have 10 users sometime you have 1000, you can't just get a connection whenever you need one and later 'release' it so the Database server does not get out of connections, which leads you to connection pooling. DriverManager
does not provide it, DataSource
does.
If you are going to program a connection pool yourself then you have to use DriverManager
, otherwise go with DataSource
.
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