Performance of StringTokenizer class vs. String.split method in Java

Question

In my software I need to split string into words. I currently have more than 19,000,000 documents with more than 30 words each.

Which of the following two ways is the best way to do this (in terms of performance)?

StringTokenizer sTokenize = new StringTokenizer(s," ");
while (sTokenize.hasMoreTokens()) {

or

String[] splitS = s.split(" ");
for(int i =0; i < splitS.length; i++)