剑指offer四十四之翻转单词顺序列

public class Solution {
    public String ReverseSentence(String str) {
        //判断字符串是否为空
        if(str.trim().equals("")){
            return str;
        }

        //按照空格分割字符串
        String[] strings = str.split("\\s+");
        StringBuffer stringBuffer = new StringBuffer();

        //逆序的字符串和空格一起，放入stringBuffer
        for (int i = 0; i < strings.length - 1; i++) {
            stringBuffer.append(strings[i] + " ");
        }

        //放入最后一个字符串
        stringBuffer.append(strings[strings.length - 1]);

        //返回结果
        return stringBuffer.toString();
    }
}