How would you describe Antonio's character in the first scene of The Merchant of Venice?

In Shakespeare's The Merchant of Venice, Antonio is revealed in Act 1.1 as a benevolent businessperson and friend to Bassanio.

Antonio's fortune is at sea in his merchant ships, and when it is known that he feels sad, his friends assume it's either because he's worried about the ships, he's in love, or because he thinks being seen as silent will make others think he is wise.  But none of these are making Antonio sad. 

In fact, his lack of worry concerning his fortune is demonstrated when he so easily tells Bassanio to use his (Antonio's) credit to raise money to go after Portia. 

Notice, too, that the venture Antonio is willing to go into debt for is not a business venture.  There is nothing in it for Antonio, except to help his friend.