"Hello World!" double reverse into "!dlroW olleH"

/**
 * "Hello World!" double reverse into "!dlroW olleH"
 * @param srcStr
 * @return
 */
public static String doubleReverseStr(String srcStr){
    if (srcStr==null){
        return null;
    }
    if (srcStr.isEmpty()){
        return null;
    }
    String trim = srcStr.trim();
    String[] split = trim.split("\\s");
    ArrayList<String> stringArrayList = new ArrayList<>();
    for (int i = 0; i < split.length; i++) {
        stringArrayList.add(split[i].trim());
    }
    ArrayList<String> stringArrayList1 = new ArrayList<>();
    for (int i = stringArrayList.size() - 1; i >= 0; i--) {
        String s = stringArrayList.get(i);
        String s1 = reverseStr(s);
        stringArrayList1.add(s1);
    }
    StringBuilder stringBuilder = new StringBuilder();
    stringArrayList1.forEach(e->{
        stringBuilder.append(e);
    });
    return stringBuilder.toString();
}

/**
 * 反转字符串
 * @param srcStr
 * @return
 */
public static String reverseStr(String srcStr){
    if (srcStr==null){
        return null;
    }
    if(srcStr.isEmpty()){
        return null;
    }
    String trim = srcStr.trim();
    StringBuilder stringBuilder = new StringBuilder();
    for (int i = trim.length()-1; i >=0 ; i--) {
        char c = trim.charAt(i);
        stringBuilder.append(c);
    }
    return stringBuilder.toString();
}