Question

I just want to understand how the database connection work through datasource.

When we set up data source, we need to provide username/password. However, if you want to retrieve a connection through datasource, we still supply another user name/password.

datasource.getConnection(username,password)

vs

datasource.getConnection();

Why do we do that? is that redundancy?

I hope someone can help me to clarify that.

Answer 1

I do not think so :
this is the code to get a connection via DataSource:

try {

    Context initialContext = new InitialContext();
    DataSource datasource = (DataSource)initialContext.lookup(DATASOURCE_CONTEXT);
    Connection con = datasource.getConnection();
    }catch(Exception e) {}

Now here I did not supply the uname/passw when obtaining a connection, as they are already specified in mysql-ds.xml [ my environ jboss , mysql ].

without JNDI:

oracle.jdbc.pool.OracleDataSource ds = new oracle.jdbc.pool.OracleDataSource();
ds.setDriverType("thin");
ds.setServerName("localhost");
ds.setPortNumber(1521);
ds.setDatabaseName("XE"); // Oracle SID
Connection con = ds.getConnection(user, password);

Please let me know if this helps.