Slow boat to China

the finale of "24" was tonight. Jack Bauer is now on "a slow boat to China". unless next season of "24".
I know I have heard of this phrase before..........what's behind it?

It was a popular song:

I'd like to get you
On a slow boat to China,
All to myself alone.
To get you and keep you in my arms evermore,
Leave all your lovers
Weeping on the faraway shore.
Out on the briny
With the moon big and shiny,
Melting your heart of stone.
Darling, I'd love to get you
On a slow boat to China,
All to myself alone.

A great exponent of this song was Jo Stafford. Try to get a hearing