class Solution {
public String reverseWords(String s) {
String[] strings = s.trim().split(" ");
StringBuilder sb=new StringBuilder();
for(int i=strings.length-1;i>=0;i--){
if (strings[i].equals("")) continue;
if(i==0) sb.append(strings[i]);
else sb.append(strings[i]).append(" ");
}
return sb.toString();
}}
trim()去掉首尾空格
split()拼接