public class Solution { public String ReverseSentence(String str) {

//特殊情况
    if(str == "") return"";
//一般情况
//按照空格分隔字符串
    String[] strSpilt = str.split(" ");
    String result = "";
    for(int i = 0; i < strSpilt.length - 1; i++){
    //按顺序拼好从开始到倒数第二个字符串
        result += strSpilt[strSpilt.length - i - 1] + " ";
    }
    //最后一个字符串较为特殊,后面无需跟空格,单独处理
    result += strSpilt[0];
    return result;
}

}