Reverse Words in a String

Given an input string, reverse the string word by word.

For example,
Given s = "the sky is blue",

return "blue is sky the".

public class Solution {
    public String reverseWords(String s) {
        //"\\s"表示空格,回車,換行等空白符，"+"表示一個或多個
        String[] parts = s.trim().split("\\s+");
        String out = "";
        if (parts.length > 0) {
            for (int i = parts.length - 1; i > 0; i--) {
                out += parts[i] + " ";
            }
            out += parts[0];
        }
        return out;
    }
}